The outer layer of a human cell allows some substances to pass through but keeps other substances out. what is the name of this layer?

a. cytoskeleton

b. cytoplasm

c. membrane

d. skin

A specialized protein in saliva breaks up starch molecules in food into smaller chains of simple sugars.

Which best describes soil found in grasslands? A. unable to support life B. wet and rich in organic matter C. moist with rocks and nutrients D. dry with little organic matter

Several processes form metal ore. Match each process to its description.

Explain how chemical weathering differs from physical weathering.

If a pea plant's alleles for height are tt, what is true of its parents? ... a. Both parents were tall ... b. Both parents were short ... c. Both parents contributed a recessive allele ... d. Both parents contributed a dominant allele.

Many virues infect only a certain type of cell because they bind to certain

What can be bio-genetically grow tissues and organs

Whole muscles can respond in a graded fashion to stimuli by varying Select one: a. the force of contraction of individual muscle fibers. b. the number of motor units recruited. c. the amplitude of the action potential. d. the frequency of stimulus.

Why does the oxygen atom in water a molecule have a negative charge

What is continental crust and ocean crust composed of