Answer:
CD4 on the surface of helper T-cells.
Explanation:
MHC class II ( major histocompatibility complex) molecules are processed from the exogenous source. The presentation of antigen on cells are important for the adaptive immune response.
MHC class II interact with CD 4 present on the surface of T helper cells. This interaction is important for the generation of an immune response. Helper T cells can release cytokines and can perform phagocytosis.
Thus, the correct answer is option (C).
The process responsible for this is mass movement.
B) the less porous, the less permeable
Porous means "full of holes."
Permeable means "stuff can go through it."
The more porous something is, the more permeable it is.
In order for plants to make their own food, they must go through a process called photosynthesis. This process occurs in the chloroplasts of a cell. To begin this process, all items needed must go to the cells of a plant. Water and nutrient are absorbed from the soil through the roots. A tube called the xylem carries only water up the stem to the rest of the plant. Gas exchange in the plants occur in the tiny pores of a leaf called the stomata. This is opened and closed by the guard cells. The food produced by this process is called ATP and it is a macromolecule known as a nucleic acid.
a.
In soil erosion, the soil is carried away from by the wind or water from the top layer of the ground. Soil formation is making soil. It can be by the deposition of the soil from water or wind
