Answer:
The answer is exogenous/non-self signals.
Explanation:
- All types of stimuli that trigger certain responses from cells are broadly classified into two categories:
- Self/ Endogenous Ligands
A ligand is a carrier molecule that can binds to a stimulus, thus, producing a signaling molecule. Ligands bind to specific receptors in or the surface of the cell.
Self/endogenous signals are signaling molecules produced by the body itself. They are part of normal cellular communication.
2. Non-self/Exogenous Ligands:
These are signals produced by a foreign source such as a pathogen or a drug administered into the body. Basically, any signal that is foreign to the body and not produced by the body itself are exogenous ligands. Exogenous ligands elicit an immune or allergic response in the body. When identified, these ligands and their source is attacked by the immune system.
Answer:
B. Mitochondria
Explanation:
The mitochondria are the organelles that supply energy to the cell. They are also known as the powerhouse of the cell.
Answer:
It is: D. it produces male and female sex cells.
Explanation:
Answer:
The type of natural selection that occur when intermediate phenotype is favored is called STABILIZING SELECTION.
Explanation:
There are 3 major types of natural selection, these are: stabilizing, directional and diversifying selection.
A stabilizing selection is said to occur when natural selection favors average phenotype by selecting against extreme variations. Stabilizing selection usually leads to decrease in genetic variation of the population concerned.
A good example of stabilizing selection is that of snakes, which have deep green color that blend completely with their environment. This set of snakes will escape from predators more than others in the population, which have color that slightly differ from deep green and which do not blend very well with the environment. Those snakes, whose colour do not blend very well with their environment will get killed more easily by the predators and with time will become extinct while those with colour that blend with the enviroment will survive and produce more offspring.
The extinction of snakes from the population will lead to decrease in genetic variation.
Answer:
Raise the beams in less time
Explanation:
As the crane carries the beams in a lesser time its energy will reduce by time
