Question

Question 7

7-Most homeostatic mechanism in animals are regulated by:

1-Group of answer choices

2-evaporative cooling

3-positive feedback loops

4-density independent populations limitations

5-negative feedback loops

Question 8

8-Which of the following is the most exclusive (smallest) group that would include an earthworm, a star fish, a crab, and a rotifer?

1-Group of answer choices

2-Lophotrochozoa

3-Eumetazoa

4-Deuterostomia

5-Metazoa

6-Bilateria

Answer 1

Ans-7. 5. negative feedback loops

Negative feedback loops are predominant mechanisms involved in homeostasis. Any process which changes the direction of stimulus is called negative feedback loop. It may either increase or decrease but not continuing as same. Example of it was low before it will now increase and if high initially it will decrease. Example is maintanence of blood sugar in animals when animals eats blood glucose level rises. Nervous system sense this and insulin is released which lowers the blood glucose while opposite happen when blood glucose lowers glucagon is released which increases blood glucose level.

Ans-8. 2. Lophotrochozoa

In protosomes the mouth developed first while in deuterostomes the a_n_u_s developed first. Protosomes are furthur divided into two large groups which are Lophotrochozoa and Ecdysozoa. The group Lophotrochozoa includes phylum platyhelminthes, rotifers, molluscas and annelids.