Answer:
According to Darwin, species evolve because those with undesirable or dangerous traits don't reproduce as much or die before they can reproduce. This causes the organisms with the most desirable traits that allow for higher reproduction or survival rates (which go hand in hand) to pass those traits on until they eventually evolve into a different species.
Positive selection tests to see if the TCR of a T-lymphocyte can recognize and bind to an MHC molecule.
<h3>What is a T-lymphocyte?</h3>
A T-lymphocyte is a special type of immune cell that is generated inside the bone marrow.
The T-cell receptor (abbreviated as TCR) is a protein located on these immune T lymphocytes.
In conclusion, Positive selection identifies if the TCR of a T-lymphocyte can recognize and bind to an MHC molecule.
Learn more about T-lymphocytes here:
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D)Electron transport chain
The cell wall gives a rigid structure to the plant, it also controls what goes in and out