Answer : Hydrogen.......:
Answer:
A) A mutation in a single gene can result in a defective protein.
Explanation:
This hypothesis states that one gene codes for one protein-enzyme, so consequently, if mutation occurs in that gene, the enzyme will not work properly. This hypothesis was very important for the fundamental discoveries of molecular biology, but it is oversimplified meaning that relationship between genes and proteins is much more complex.
Answer:
Prenatal.
Explanation:
The sexual reproduction may be defined the process of fusion of the male sperm and female ovum that leads to the formation of the zygote. Zygote is diploid in nature.
The prenatal development includes all the stages that are involved in the development of the single cell till the completion of the nine months of the fetus. The development of all organs and the process of the cell specification all occurs in the prenatal development stage.
Thus, the answer is prenatal.
It's controversial because the best source of stem cells is a human embryo (an aborted fetus).
