<span>a strong downward current of air from a cumulonimbus cloud, usually associated with intense rain or a thunderstorm.</span>
Answer:
1- A species can migrate over long distances because they have metabolisms suitable for that, adaptation mechanisms to withstand different adversities. They usually do it to be able to reproduce in ideal climaxes or feed on certain living things or plant species.
2-The existence of oil fields, or oil towers for the manufacture of fuel.
3-Implement electric cars or batteries that do not depend on fuels such as diesel, naphtha.
Explanation:
In this exercise it is good to highlight that during the migration of animals of different species their numbers decreased both to reach the territory to which they migrate and by human intervention in nature in a harmful way.
Ans.
Steroids are defined as active organic bio-molecules, having four rings with a specific molecular configuration. Steroids play role in two major functions: as hormones or signaling molecules and as structural components of plasma membrane.
Examples of steroid hormones are estrogen, progesterone, and cortisol. Thus, the correct answer is 'option b). they serve as chemical messengers.'
