Answer:
Three nucleotide
Explanation:
Three nucleotides are required to code for one amino acid. There are four types of nucleotides A, T, G, C which make DNA. So a doublet of nucleotide code which involves only two nucleotide would be insufficient to code for 20 amino acids because if 4 different nucleotide is taken two at a time then it can only produce 16 amino acid(4²=16).
But if we take three-nucleotide than the number reaches 64 which is more than sufficient to code for 20 different amino acids(4³= 64). Therefore 3 nucleotides are needed to code for an amino acid.
The base which is Uracil or Thymeine
The male contributes the sperm and the female contributes the egg or ovum. Then they meet in the fallopian tube and becomes a zygote.
Depth, flow, temperature, and chemistry of overlying water
Answer:
Immediately, the pathogen has been recognized:
Macrophages acts as the first line of defence by engulfing pathogens identified by antigens which will now present the antibody shape to a helper T cell.
The Helper T cells produce a signal to plasma and Memory B cells to yield antibodies that attach to the antigens. The cytotoxic cells that leads to cell death are activated by the helper T cells.
Antibodies helps to immobilize pathogen for macrophage to feed on.
if the pathogen comes back a 2nd time the memory cells helps in quick and efficient recovery by producing the specific B and T cells for the antigen.
