Answer:
Option B, 
Explanation:
Given-
The average surface area of one foot pad of an elephant is

Weight of an Asian elephant is
newton
As we know, pressure is equal to total weight divided by total area of the surface on which it is concentrated.
Thus, pressure on one foot pad of elephant is 

Hence, option B is correct answer
After the macrophage fails the Helper T Cell stimulates the B cells if pathogen is extracellular and Cytotoxic T Cells if the pathogen is intracellular. Once the pathogen is killed the B Cells create Memory B Cells and the Killer T Cells create memory T Cells.
Answer: The answer should be A: Precipitation.
Explanation: When we take a look at this question, it mentions that there is dew, fog, and clouds on the planet. Infiltration would have probably been evaporated from the ground and became a cloud. The dew and fog would be the condensation. The astronomers notice that there is never any rainfall, and precipitation in the water cycle is rainfall. So therefore, the missing part of the water cycle would be precipitation
Answer:
Letter a) Protists would have less permeable membranes than those in hypotonic or Isotonic environments, wlowing less water to enter the coll. Also, they could possibly develop higher salt concentration within the cell to retain water.
Tiny regions at the surfaces of neurons and different cells which are touchy to neurotransmitters or hormones are called receptors.
The required details for receptors in given paragraph
Cellular receptors are proteins both internal a mobileular or on its floor which acquire a sign. In everyday physiology, that is a chemical sign in which a protein-ligand binds a protein receptor. The ligand is a chemical messenger launched with the aid of using one mobileular to sign both itself or a exceptional mobileular. Receptors are proteins that bind to outside messengers to create a chain of downstream consequences that mediate a selected reaction withinside the mobileular. Receptors have a ligand-binding area that acknowledges the particular ligand and the effector area that undergoes conformational modifications to provide a downstream event.
Receptors are available in many types, however they may be divided into categories: intracellular receptors, which can be determined internal of the mobileular (within side the cytoplasm or nucleus), and mobileular floor receptors, which can be determined within side the plasma membrane.
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