The upper part of graft combination is called scion.
Helicase breaks hydrogen bonds of the DNA helix. Therefore it “unzips” the DNA helix and separates the strands for free complementary RNA strands which use the strands as a template during replication.
Answer: This is a positive feedback loop.
Explanation:
The protein digestion in the body is an example of the positive feedback. The gastric secretions is stimulated chiefly by the action of three chemicals.
These chemicals are acetylcholine, histamin and gastrin. These chemicals stimulate the parietal cells to secrete HCL and intrinsic factors.
The chief cells secrete pepsinogen in response to the gastrin and ACh. As the dietary proteins are digested, it breaks down the amino acids and peptides.
This stimulates the G cells of the stomach to secrete more gastrin. This is how the positive feedback loop for the protein digestion works.
The correct answer is b, antigens
