Answer: option A
Explanation: As demonstrated by the Hardy-Weinberg principle, the dominance or recessiveness of an allele does not determine its frequency in a population.
Swamps or maybe those in the desert. In swamps, the soil is too loose for animals to burrow without it caving in. In deserts, since the climate "rising" its getting to hot and dry for animals to burrow without the sand caving in when an animal walks above it.
The greenhouse effect traps heat near the surface and raises the temperature, just like a blanket. :)
This is because elements are pure substances with only one atom. When two or more elements are combined, you get compound elements; which allows for more substances to be created.