Answer:
antibodies are produced in response to infection and that these antibodies are designed to specifically target particular antigens and bind tightly to them.
Answer:
The kidneys take of up more Ca2+ and release vitamin D. The bones release Ca2+. The intestines increase reabsorption of Ca2+.
All viruses have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can't survive without a host. They can only reproduce by attaching themselves to cells. Unlike bacteria, most viruses do cause disease, and they're quite specific about the cells they attack.
A Sperm attaches to an Ooctye
I think it is NAD, this ensures that the NAD can go back to glycolysis where it can again be reduced and go back through anaerobic respiration.
