Answer:
A cell membrane is made of two layers.
The cell membrane is composed by a phospholipid bilayer where the interior side is hydrophobic and non-polar, while the outside is hydrophilic and polar
Pores and proteins in the cell membrane allow passage through it.
The pores and proteins in the cell membrane have several functions such as, for example, cell signaling (proteins) and selective transport (pores)
Answer:External respiration occurs in the lungs where oxygen diffuses into the blood and carbon dioxide diffuses into the alveolar air. Internal respiration occurs in the metabolizing tissues, where oxygen diffuses out of the blood and carbon dioxide diffuses out of the cells.
Explanation:
Natural selection refers to the phenomenon by which the species in a population possessing the tendency to get adapted in a condition enhance in numbers in comparison to those who exhibit fewer adaptation capacities over a number of generations.
In other words, it can be stated as the non-random and differential development of distinct genotypes function to sustain favorable variant and to eradicate less favorable variants. Some of the conditions are required for the process of natural selection to take place.
These are heredity, reproduction, variation in individual characters, and variation in the fitness of organisms among the members of the population. If the conditions are met, then the phenomenon of natural selection occurs by default.
