'Red shift' is a key concept for astronomers. The term can be understood literally - the wavelength of the light is stretched, so the light is seen as 'shifted' towards the red part of the spectrum.
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Answer:
meiosis I
Explanation:
Reduction of the number of sets of chromosomes occurs during meiosis I.
During Meiosis I crossing over of genetic material occurs between chromosome pairs
The jet stream flows west to east
Answer:
Immune system of the body helps in fighting with the infectious agents that are foreign for the body. So the immune system protects us from infection.
When any foreign substance(antigen) comes in the body B-lymphocyte recognize it by binding the antigen through its receptor. After recognizing the antigen, B cell divides into antibody-producing plasma cell and memory cell.
Antibodies produced by plasma cells help in destroying the antigen by getting the antigen recognized by phagocytic cells or by complement activation.
B cells are antigen-presenting cell which present antigen to T cell and then T cell activates and produce chemicals that kill the antigen. Therefore the immune system has many immune cells that activate when an antigen comes in the body. This is how the immune system functions.
