Answer:
Cuticle
Explanation:
Plant cuticle is a waxy covering over the aerial epidermal cells of all the plants. Waxes are composed of cutin and a various organic solvent-soluble lipids. The cuticle is an extracellular hydrophobic layer which provides protection against desiccation and external environmental stresses. In other words the cucticle helps to retain water and give plants an adavanthe to live terrestrial life.
The point that makes is that these are problems which can not be solved.
<u>Explanation:</u>
The point that Huxley makes about the nature of human and the nature of the communities of the human is that these are certain problems and such problems are not solvable.
Social engineers like Mustapha Mond ends up asking the questions like what is that thing which prevents the people from being happy in their lives. And after knowing that thing, there should be efforts made to remove the source of unhappiness of the people.
It is useful for an ecologist to identify the keystone species in an ecosystem because the keystone species is important to maintaining the stability of an ecosystem, and any changes in the keystone species population shows that there is changes in ecosystem health.
