Because an antibody is "made" relative to the antigen, but kept at low levels when you are exposed the first time ("primary immune response"). The second time you're exposed to the same antigen, memory cells recognize it and the body produces a high level of antibodies, and the level of antibodies usually remains higher for a longer time ("secondary immune response"). This is your basic immune response (primary and secondary).
This explains exactly why vaccines are effective to extremely effective.
Answer:
cell
tissue
organ
system
human organism
Explanation:
unicellular organisms only have one cell since two or more cells form a tissue their level of organization is restricted to cell
cell
two or more cells form a tissue
two or more tissue forms an organ
two or more organs form a system which must work in coordination for efficiency
two or more systems make up a human organism
Answer:
The cell organelles are the functional structures present inside the cell. Some of the organelles such as nucleus, mitochondria, chloroplast, Endoplasmic Reticulum, Golgi Complex etc are membrane-bound. Each organelle inside the cell has a different function to carry out. For example, the nucleus is the organelles which stores and protects the genetic material. Ribosomes are the organelles where a protein is formed. The Golgi- complex is the site where the proteins are modified and packaged.
Thyroxine is an important hormone released into the bloodstream by the thyroid gland in the body. When tyroxine is released into the blood stream, it moves through certain organs such as the kidney and liver, where most of it is changed to an active form known as triiodothyronine. Thyroxine perform important roles in brain development, heart and digestive functions, bone maintenance, controlling muscle and metabolic rate of the body.
<span>The migration routes of Homo sapiens reveal
that they went through many environmental and physical challenges but adapted
everything much quickly in comparison to the other animals. The evolution
allowed other species also to adopt these changes but it took them a long time
to fit in the new environment, a sub species of a species adopted the new and
the previous one could not, but Homo sapiens invented ways and tools to combat
and evolve much quickly. It included their living, dietary needs, clothing and
much more.</span>