Answer:
a. heart development.
Explanation:
As the third week of fetal development starts, the process of formation of blood vessels begins. Also, the splanchnic mesoderm in the head end of the embryo forms heart on days 18 and 19. Since it develops heart, this part of the mesodermal cells is called the cardiogenic area. The underlying endoderm sends the induction signals to these mesodermal cells to form a pair of endocardial tubes that gradually develop into a single primitive heart tube.
This primitive heart begins to beat by the end of the third week of development. Therefore, any drug that affects fetal development during the first 20 days of the pregnancy might affect the development of the heart.
Igfed if we can get the one we e do have to do it again next time
<span>In
the process of polymerization, a chain of similar smaller molecules
called monomer join together to create very large molecules called
polymer. Through this chemical reaction, water is created as a
by-product. In contrast to hydrolysis or breaking down of polymers, a
water molecule is used to break the covalent bond that hold the
components of a polymer.</span>
