The main molecules present in the plasma membrane are<em><u> phospholipids</u></em>, those molecules are made of a polar, hydrophil end(glycerol with a phosphate group attached) and two non-polar, hydrophobe ends(two fatty acids rests). The cell identity is determined by <u><em>proteins </em></u>present in the membrane, a very important type of protein that determines the identity of a specific cell is called marker. The membrane fluidity is reduced by a lipid with a ring structure, <u><em>cholesterol</em></u>, this molecule belongs to a class of biomolecules called steroids.
Answer:
The oxygen is used in the cell wall to store nutrients hope this answer helps
Positive - Due to urbanization, the people of rural areas settle in urban cites. These reduces the labour work which was done in rural areas and as they get water and electricity. The reduced labour work help them in maintaining their physical health
Negative - If people continues to enjoy the facilities and sit ideally doing nothing is much more worse than the above one. It causes obesity and can ultimately lead to heart attack
Alfred Russel Wallace, a biologist, naturalist and anthropologist who studied life in the tropics of Indonesia came up with the same idea of natural selection as Charles Darwin and prompted Darwin to publish his Origin of Specie sooner rather than later. He also studied the geographic distribution of species and as as well he was a social activist who criticized capitalism and warned of damage to the environment from man's economic activities.
