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.

by drinking easy

very easy

links? do you have a link? i don't see anything?

the answer

b.) bowling ball

phosphorus cycle

explanation:

the phosphorus cycle is the way that compounds of the element phosphorus, an essential nutrient, are recycled in the environment. plants absorb phosphorus compounds from the soil, and decaying organic matter, including both plant matter and animal droppings, returns it to the soil. phosphorus is a vital part of atp, the energy currency of all cells, and is vital to all forms of life.