Answer: Cells have receptors because Receptors let the cell know when to let things in and out of the cell.
Explanation:
Cell receptors also called transmembrane receptors are proteins located on the surface of a cell (extracellularly) or inside the cell which receive signals that alters the functions of the cell. The functions of the cells which can be altered includes the alteration in gene transcription and the cell morphology.
Cell receptors are generally categorizes into the following groups:
--> Internal receptors
--> cell surface receptors
--> ion channel receptors
--> G protein coupled receptors
--> enzyme linked receptors
Interaction of cell membrane receptors with specific ligands that bonds to the receptors causes conformational changes in the receptor protein. This in turn, enzymatically activates the intracellular part of the protein or induces interactions between the receptor and the proteins in the cytoplasm that act as second messengers, thereby relaying the signal from the extracellular part of the receptor to the interior of the cell. This enables the cell to know when to let things in or out of it through the information conveyed.
Answer: E = 
Explanation: The formulae for intensity of an electric field of a solid metal sphere relative to a point is given below
r
where
,
, r = 0.1m r = is the position vector of the charge.
it has been stated in the question that the charge is placed at the center thus it has no position vector.

Answer:
When electric voltage is applied, an electric field within the metal triggers the movement of the electrons, making them shift from one end to another end of the conductor. Electrons will move toward the positive side.
Answer:
<h2>59.5 N</h2>
Explanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question we have
force = 70 × 0.85
We have the final answer as
<h3>59.5 N</h3>
Hope this helps you
Answer:
There are six major nutrients: Carbohydrates (CHO), Lipids (fats), Proteins, Vitamins, Minerals, Water.
Explanation: