<span>The answer is Due to heating of the air by the engine exhaust. Contrails are formed when the hot exhaust of the plane engines is rapidly cooled by the cold air in the upper atmosphere. The water vapor in the engine exhaust, formed in the combustion of fuel, freezes immediately to ice crystals due to the low pressure and -36oC temperatures in the 8000 m altitude in which the planes cruise. </span>
Answer:
Evolution is a gradual change in the inherited traits of a population over many generations. Natural selection is a mechanism where the members of a population best suited to their environment have the best chance of surviving to pass on their genes.
Answer:
The metabolic chemical reaction is reversible, and they too would attain equilibrium if they take place in a test tube separately. However, if a cell attains metabolic equilibrium it is considered as dead. Thus, a cell in the body is not in equilibrium.
The spontaneous flow of substances within and outside of the cell prevents the metabolic pathways from attaining an equilibrium, and the cell persists to perform the work all through its life. This principle is demonstrated by the open hydroelectric system.
Answer:
it is summer and north America
