B contraction :) it's a basic function of all muscles.
Cancerous cells often produce tumor markers as well as its own cancer cells that act as antigens that can be recognized by antigen presenting cells and be presented to natural killer (NK) cell progenitors that are found in the spleen, lymph nodes, thymus, and other lymphoid organs. With malignancy, the production of NK cells will be increased. NK cells works by killing cells that do not have an inhibitory signal (i.e. cancer cells) and preserving cells that do have an inhibitory signal (i.e. normal body cells).
I hope this helps the answer is A
Answer:
Mutualism: It is a type of symbiotic relationship between two organisms in which both the organisms gets benefits to each other.
For example, in leguminous plants a bacteria is present in the roots of the plants and make symbiotic relationships with each other. In this relationship, plant provides habitat and food to the bacteria and in return the bacteria fixes atmospheric nitrogen for the plant and both get benefit.
1. False
Speciation is the formation of new species from a population of species. This process has three main stages: isolation, where the population is separated; adaptation, where the isolated population adapts to the new environment; and reproductive isolation, where the two populations can no longer breed to produce fertile offspring.
2. Behavioral isolation
This occurs when there is a difference in mating rituals or other behaviors which prevent interbreeding.
