The palisade mesophyll has long cylinder shaped cells, lots of chloroplasts, cells closely packed together and large size of cells.
Answer:
a. Biomagnification
Explanation:
Biomagnification is the name given to the progressive accumulation of substances from one trophic level to another along a food chain. Thus, the substance will have its highest concentration in individuals who occupy trophic levels furthest from producers.
For biomagnification to occur, substances must be fat soluble (lipid soluble) and thus adhere to living tissues. Another feature of substances that undergo biomagnification is that they are generally not biodegradable or metabolized by the body.
The phenomenon is quite common with heavy metals (lead; mercury) and certain chlorinated and aromatic organic compounds with higher molecular mass, such as the insecticide DDT.
Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
