No system is closed off by it surroundings.
A. Immune system
It helps our bodies fight everything that comes in our path.
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.
Answer:
The correct answer will be option-A
Explanation:
The practice of marriage is practised in every culture which is associated with the union of the boy and a girl to which they are committed to spending a life-long relationship.
The studies on the preferences shown by the woman who has to get married have to look for the boys who are career-oriented which could provide a good earning to feed them and their family and fond of children to establish a family which will help develop the stronger relationship between them.
The girls ignored the attractiveness feature of their spouses as in a long term relationship attractiveness does not matter because of the feeling of love and strong bond between them.
Thus, option-A is the correct answer.
Answer: NO.Not a MONOPHYLETIC group yet.
This because MYRIMICA one of the decendant of most common ancestors of this group has been left out.Therefore MYRIMICA should be added.
Explanation:
