Biomass is the total mass of living things at each what?
Options:
- (A) trophic level
- (B) important habitats
- (C) Energy.
- (D) food and shelter
- (E) Power plants
- (F) animals
- (G) body water
- (H) heat energy
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Let's think first: Biomass is the total mass of organisms at a trophic level. Most living things are called organisms. Biomass is the total mass of living things at a trophic level.... So the answer is [(A)]

Changing the structure of a chromosome can be what to an organsim?
Options:
- (A) massive damage
- (B) mechanical
- (C) beneficial
- (D) harm them
- (E) negative
- (F) dangerous
- (G) homogenous
- (H) Damages them
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Let's think first: Mutations may change the structure of a chromosome or just change a single nucleotide. Most mutations are beneficial to the organism. Changing the structure of a chromosome can be beneficial to the organism.... So the answer is [(C)]

Changes in what are essential for evolution to occur.
Options:
- (A) color of leaves
- (B) genetic material
- (C) learned behavior
- (D) synthetic material
- (E) the body's largest organ
- (F) acquired characteristics
- (G) sensory neurons
- (H) Most plants
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Let's think first: Mutations are essential for evolution to occur. Mutations are changes in the genetic material. Changes in the genetic material are essential for evolution to occur.... So the answer is [(B)]

What is essential for change over time?
Options:
- (A) Light
- (B) Chemical energy
- (C) Essential oil.
- (D) evaporation
- (E) Currency.
- (F) Clocks.
- (G) colors
- (H) Mutations.
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Let's think first: Mutations are essential for evolution to occur. Evolution Evolution means change over time. Mutations are essential for change over time.... So the answer is [(H)]

Flowing water can slowly _ carbon in limestone.
Options:
- (A) alter
- (B) destroy
- (C) erode
- (D) allow growth
- (E) dissolve
- (F) heat
- (G) a solute
- (H) rain
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Let's think first: Flowing water can slowly dissolve carbon in sedimentary rock. Limestone is an organic, sedimentary rock. Flowing water can slowly dissolve carbon in limestone.... So the answer is [(E)]

What do plants build their cell walls from?
Options:
- (A) By wind and rain
- (B) Deposition
- (C) Deposition.
- (D) algae
- (E) Chemical energy
- (F) plant wall
- (G) plant material
- (H) polysaccharides
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Let's think first: Plants use cellulose for their cell walls. Another important polysaccharide is cellulose. Plants use a polysaccharide for their cell walls.... So the answer is [(H)]