Answer:
The correct answer would be d. thymus.
The thymus is a specialized lymphoid organ of an immune system.
It serves as the site for training and maturation of T-lymphocytes or T cells.
It is composed two identical lobes each containing outer region termed as cortex and inner region termed as medulla.
T-cells are first trained and selected in the cortex region via positive selection. In this, T cells which are able to bind to foreign antigens are selected and rest are degraded.
The selected T cells then move in the medulla region where they are selected by negative selection. In this, the T cells which binds to self-antigens are degraded and rest survive to become functional T cells.
Answer:
is a process in which deep, cold water rises toward the surface. ... Water that rises to the surface as a result of upwelling is typically colder and is rich in nutrients. These nutrients “fertilize” surface waters, meaning that these surface waters often have high biological productivity
Explanation:
Answer:
I think it is B chloroplasts. Because cilia is something found in both of the cells, an same goes for mitochondria and ribsomes.
Explanation:
Your answer is D. thermal energy.
Answer - Compare population growth problems in more developed countries and less developed countries: More developed countries try to reduce the birth rate, but are unable to. Less developed countries have high death rates.