Scientists have successfully cloned animals, including mammals such as sheep. Which statement provides the most likely reason that a human has not yet been cloned?

4) Some people consider human genetic experiments

unethical.

Explanation:

1) Humans have DNA that is structurally very different from

other mammals.

2) Cloning can only he performed on animals that normally

reproduce asexually.

3) Human genes are made of too many different types of

simple sugars.

4) Some people consider human genetic experiments

unethical.

The statement that provides the most likely reason that a human has not yet been cloned is that some people consider human genetic experiment unethical.

Option 1 is incorrect because human DNA is similar in structure to other living organisms with components such as a phosphate group, a deoxyribose sugar and purine/pyrimidine bases.

Option 2 is incorrect because cloning is not limited to asexually reproducing organisms only. Sheep, for example, produces only sexually and has been successfully been cloned.

Option 3 is incorrect because human genes, just like every other organisms is consist of DNA with deoxyribose pentose sugar being one of the components. The situation of too many different types of simple sugars doe not arise.

The correct option is 4.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.