3. Variation within a species occurs through a. Mutation
b. sexual reproduction
c. Both mutation and sexual reproduction

4.Which of the following statements is true?

a. Antibiotics kill all bacteria that they encounter

b. Antibiotics don't kill bacteria which have a pre-existing trait allowing them to break

c. Antibiotics don't kill bacteria that evolve an allele allowing them to break down the down the antibiotic antibiotic after they encounter the antibiotic

d. None of these.

not the best question format lol but what i think might as scale color is controlled by a single gene with two alleles, the green allele and the yellow allele. when moths that are homozygous for green scales are mated with moths that are homozygous for yellow scales, 100% of the offspring have green scales.

the answer is z.

the human body has five levels of organization. level 1: cells. cells are the basic units of life and form the first level of organization. cells in the human body have specific functions. examples include nerve cells, blood cells, liver cells, and so on.