Rhode Island Next Generation Science Assessment — Grade 8

Which organelle is primarily responsible for converting glucose and oxygen into usable cellular energy in the form of ATP during cellular respiration?

• AChloroplast
• BMitochondrion
• CEndoplasmic reticulum
• DGolgi apparatus

A student observes a plant cell and an animal cell under a microscope. Which organelle is present in the plant cell to provide rigid structural support but is absent in the animal cell?

• ACell wall
• BCell membrane
• CCytoplasm
• DRibosome

Which organelle absorbs radiant sunlight energy to produce glucose and oxygen gas from carbon dioxide and water?

• AMitochondrion
• BRibosome
• CChloroplast
• DNucleus

Which statement BEST describes the primary function of the semi-permeable cell membrane in both eukaryotic and prokaryotic cells?

• AIt synthesizes carbohydrates and proteins required for cell growth.
• BIt replicates genetic material prior to cell division.
• CIt generates ATP by breaking down nutrients.
• DIt regulates the movement of substances into and out of the cell to maintain homeostasis.

Which organelle houses the genetic blueprint (DNA) and directs all cellular growth, development, and protein synthesis activities?

• ANucleus
• BVacuole
• CGolgi body
• DLysosome

Which cellular structure contains hydrolytic digestive enzymes designed to break down cellular waste, pathogens, and damaged organelles?

• APeroxisome
• BLysosome
• CMitochondrion
• DNucleolus

How does the structure and function of the vacuole differ between a mature plant cell and a typical animal cell?

• AAnimal cells contain one large central vacuole for photosynthesis, while plant cells cont…
• BPlant cells lack vacuoles entirely, relying instead on cell walls for all liquid storage.
• CAnimal cells have rigid cell walls surrounding their vacuoles, whereas plant cell vacuole…
• DPlant cells feature a single large central vacuole that maintains turgor pressure, wherea…

Which set of substances represents the required chemical REACTANTS for green plants to carry out photosynthesis?

• ACarbon dioxide, water, and light energy
• BGlucose, oxygen, and ATP
• CNitrogen gas, glucose, and soil nutrients
• DOxygen, water, and carbon dioxide

What are the primary chemical PRODUCTS generated during aerobic cellular respiration in animal and plant mitochondria?

• AGlucose and oxygen gas
• BSunlight, water, and starch
• CCarbon dioxide, water, and ATP energy
• DLactic acid, oxygen, and nitrogen

Which balanced chemical equation correctly models the process of photosynthesis?

• AC6H12O6 + 6 O2 -> 6 CO2 + 6 H2O + ATP
• B6 CO2 + 6 H2O + Light Energy -> C6H12O6 + 6 O2
• C6 CO2 + C6H12O6 -> 6 H2O + 6 O2 + Light Energy
• D6 O2 + 6 H2O -> C6H12O6 + 6 CO2 + Light Energy

How do photosynthesis and cellular respiration work together to cycle carbon through an ecosystem?

• APhotosynthesis creates new carbon atoms, while cellular respiration destroys excess carbo…
• BBoth processes absorb carbon dioxide from the atmosphere, lowering carbon levels permanen…
• CCellular respiration converts atmospheric carbon dioxide into mineral rocks, while photos…
• DPhotosynthesis removes carbon dioxide from the atmosphere to build organic molecules, whi…

Why do plant leaves appear green when viewed under white sunlight?

• AChlorophyll absorbs blue and red wavelengths of light while reflecting green wavelengths…
• BChlorophyll absorbs green light exclusively and converts it directly into oxygen gas.
• CPlant cell walls absorb all visible wavelengths equally, emitting green fluorescence.
• DMitochondria emit green light as a byproduct of ATP synthesis.

A student increases the light intensity surrounding an aquatic plant and measures the rate of photosynthesis. Initially, the rate increases, but at very high light intensities, the rate levels off. What is the MOST plausible explanation?

• AThe plant runs out of chlorophyll molecules permanently.
• BLight energy begins destroying water molecules faster than they can be replaced.
• CAnother factor, such as carbon dioxide concentration or temperature, has become the limit…
• DCellular respiration stops completely when light intensity becomes high.

In an experiment investigating aquatic plant photosynthesis, a student counts gas bubbles released by Elodea submerged in water. Which gas forms these bubbles and serves as direct evidence of photosynthetic activity?

• ACarbon dioxide
• BOxygen
• CNitrogen
• DMethane

Which statement BEST summarizes the mechanism of evolution by natural selection?

• AOrganisms intentionally change their genes to survive harsh environmental shifts.
• BAll individuals in a population develop identical physical traits during their lifetimes.
• CIndividuals with inherited traits best suited to their environment are more likely to sur…
• DStronger organisms eliminate weaker organisms through direct physical combat.

What are the TWO primary biological sources of novel genetic variation within a sexually reproducing population?

• AAsexual budding and environmental acclimation
• BDNA mutations and genetic recombination during sexual reproduction
• CMitotic cell division and organelle duplication
• DSelective breeding and artificial fertilization

How does a population of bacteria become resistant to an antibiotic over time?

• ABacteria with pre-existing mutations conferring resistance survive antibiotic exposure an…
• BThe antibiotic causes all individual bacteria to instantly mutate their cell walls for pr…
• CBacteria learn to avoid absorbing the antibiotic after multiple exposures.
• DThe antibiotic selectively kills resistant bacteria, allowing non-resistant bacteria to m…

During the Industrial Revolution in England, dark-colored peppered moths became much more common than light-colored moths near industrial cities. What selective pressure drove this change?

• AIncreased toxic coal dust in air made light moths turn dark overnight.
• BSoot covered tree trunks, making dark moths better camouflaged against bird predators.
• CDark moths ate coal dust to gain extra energy for flight.
• DLight moths migrated to warmer ocean climates.

Which term describes an environmental factor—such as predator presence, food scarcity, or disease—that affects an organism's ability to survive and reproduce?

• AGenetic drift
• BSelective pressure
• CArtificial selection
• DGene flow

Darwin observed that finch species on different Galapagos Islands had distinct beak shapes. How does natural selection explain these differences?

• AFinches stretched their beaks while reaching for food, passing longer beaks to offspring.
• BAll finch species originally had identical diets, but beak shapes changed randomly withou…
• CIsland populations adapted over generations as finches with beak shapes suited to availab…
• DFinches mated with different bird species to instantly acquire new beak types.

A natural disaster drastically reduces a population of wild deer from 5,000 to 50 individuals. How is this genetic bottleneck event likely to impact the surviving population's future adaptation?

• AGenetic variation is reduced, making the population less adaptable to future environmenta…
• BGenetic variation increases dramatically because surviving deer mutate faster.
• CThe population becomes immune to all future natural disasters.
• DNatural selection ceases to operate in small populations.

Where are genes located within a eukaryotic plant or animal cell?

• AFloating freely in the cell wall
• BInside the central vacuole membrane
• CInside ribosome protein channels
• DOn structures called chromosomes located inside the nucleus

In pea plants, the allele for tall stems (T) is dominant over the allele for short stems (t). What phenotype will a heterozygous plant with genotype Tt express?

• ATall stems
• BShort stems
• CMedium stems
• DNo stems

Two pea plants with heterozygous genotypes for flower color (Bb x Bb) are crossed. Purple (B) is dominant to white (b). What percentage of the offspring is predicted to have white flowers?

• A0%
• B25%
• C50%
• D75%

According to the complementary base-pairing rules of DNA, which nitrogenous base pairs with Adenine (A)?

• ACytosine (C)
• BGuanine (G)
• CThymine (T)
• DUracil (U)

Which statement correctly distinguishes an organism's genotype from its phenotype?

• AGenotype is the specific combination of alleles, whereas phenotype is the observable phys…
• BGenotype describes physical appearance, whereas phenotype describes DNA base sequences.
• CGenotype changes constantly throughout life, whereas phenotype remains permanently fixed.
• DGenotype is inherited from one parent only, whereas phenotype is inherited from both.

When a purebred red flower (RR) is crossed with a purebred white flower (WW), all offspring exhibit pink flowers (RW). Which pattern of inheritance does this demonstrate?

• AComplete dominance
• BSex-linked inheritance
• CPolygenic inheritance
• DIncomplete dominance

A human pedigree shows a genetic condition that skips generations. Neither parent expresses the condition, but one of their children has it. What is the MOST likely mode of inheritance?

• AAutosomal dominant
• BAutosomal recessive
• CMitochondrial dominant
• DY-linked inheritance

Which group of organisms occupies the foundational base of an ecological food web by converting solar energy into food?

• APrimary consumers
• BAutotrophic producers
• CSecondary consumers
• DApex predators

What critical ecological role do decomposers—such as fungi and soil bacteria—play in maintaining ecosystem sustainability?

• AThey generate solar energy for primary producers.
• BThey reduce carbon dioxide levels by storing it as oxygen gas.
• CThey convert atmospheric nitrogen directly into water molecules.
• DThey break down dead organic matter and recycle vital nutrients back into the soil and ec…

In an energy pyramid, approximately what percentage of stored chemical energy is transferred from one trophic level up to the next higher level?

• A10%
• B50%
• C90%
• D100%

A marine ecosystem experiences a severe decline in its sea otter population. Sea otters eat sea urchins, and sea urchins consume kelp. What is the MOST likely consequence of removing sea otters?

• AKelp forests expand rapidly and overcrowd the ocean floor.
• BSea urchin populations explode, leading to overgrazing and destruction of kelp forests.
• CFish populations relying on kelp forests increase dramatically.
• DSea urchins starve to death immediately.

Why do non-native invasive species often outcompete native species when introduced into a new ecosystem?

• AInvasive species require no water or nutrients to survive.
• BInvasive species frequently lack natural predators, parasites, or competitors in the new…
• CInvasive species alter the local climate to match their native habitat.
• DNative species voluntarily stop reproducing when new organisms arrive.

Bees harvest nectar from flowering plants to make honey, while simultaneously transferring pollen between flowers to enable plant reproduction. Which type of symbiotic relationship is this?

• AParasitism
• BCommensalism
• CPredation
• DMutualism

A scientist tracks a population of field mice over 20 years. After growing exponentially, the population levels off and oscillates around 400 individuals. What ecological factor determines this population limit?

• ACarrying capacity dictated by limiting environmental resources
• BCellular respiration limits within individual mitochondria
• CThe global rate of photosynthetic carbon fixation
• DComplete exhaustion of genetic variation

Which subatomic particles are located inside the nucleus of an atom?

• AProtons and neutrons
• BElectrons and protons
• CNeutrons and electrons
• DQuarks and photons only

The atomic number of an element on the periodic table directly identifies which value?

• ATotal number of neutrons in the nucleus
• BTotal atomic mass in grams
• CNumber of protons in the nucleus of an atom of that element
• DNumber of chemical bonds the atom can form

Why do elements in the same vertical column (group) of the periodic table display similar chemical properties?

• AThey have the exact same atomic mass.
• BThey have the same number of valence electrons in their outermost energy level.
• CThey contain identical numbers of neutrons.
• DThey exist in the same state of matter at room temperature.

A neutral sodium atom (atomic number 11) loses one electron during a chemical reaction with chlorine. What is the net electrical charge of the resulting sodium ion?

• A-1
• B0
• C-2
• D+1

Carbon-12 and Carbon-14 are two isotopes of the element carbon. How do these two atoms differ subatomically?

• ACarbon-14 has 2 more neutrons than Carbon-12.
• BCarbon-14 has 2 more protons than Carbon-12.
• CCarbon-14 has 2 more valence electrons than Carbon-12.
• DCarbon-14 has a negative charge while Carbon-12 is positive.

Where are metals, nonmetals, and metalloids located relative to one another on the modern periodic table?

• AMetals are on the far right, nonmetals on the left, and metalloids at the very bottom row.
• BNonmetals occupy the left side, metals are in the middle, and metalloids are on the top r…
• CMetals occupy the left and central sections, nonmetals reside on the upper right, and met…
• DMetals and nonmetals are randomly scattered without structural order.

An atom of iron has a mass number of 56 and an atomic number of 26. How many neutrons are present in its nucleus?

• A26
• B30
• C56
• D82

What does the Law of Conservation of Mass state regarding a chemical reaction taking place in a closed container?

• AThe total mass of the products is always double the reactant mass.
• BThe total mass of the products equals the total mass of the reactants because matter is n…
• CMass decreases because chemical energy is converted into physical mass.
• DMass increases if gas bubbles form inside the vessel.

Which observation provides the BEST evidence that a chemical reaction has occurred rather than a physical change?

• AIce melting into liquid water when heated
• BMixing two clear liquids results in a temperature spike and formation of a yellow solid p…
• CSugar dissolving completely in warm tea
• DCutting a wooden board into smaller pieces

Consider the unbalanced chemical equation: CH4 + ? O2 -> CO2 + 2 H2O. What coefficient for oxygen gas (O2) balances this equation?

• A2
• B1
• C3
• D4

A student mixes two chemicals in a beaker and observes that the beaker feels noticeably cold to the touch. What type of reaction occurred?

• AExothermic reaction
• BNuclear fusion reaction
• CEndothermic reaction
• DPhysical condensation reaction