<span>Norepinephrine uses the Second
Messenger System, which means, cells signal to each other what molecules have
been released that will trigger a physiological reaction. </span>
<span>
This phenomenon is activated after the ligand (ion or molecule) is bonded to its receptor
(protein molecule), creating a variation that causes a chain-reaction, that will
finally activate the Second Messenger. The latter will activate intercellular
molecules that will be able to control the cell’s activity. </span>
Answer: D. Dwarf Planets
Explanation:
Dwarf planets have round shape and orbit the sun. They do not clear their orbits due to smaller gravitational pull and hence, cannot be classified as a planet. A dwarf planet may or may not have moons. Dwarf planets are smaller in size than planets.
Pluto was once classified as planet but was demoted to dwarf planet as many other similar sized objects were found in its neighborhood in Kuiper belt (Eris, Haumea, Makemake) . One dwarf planet is present in asteroid belt as well. It is the largest object in the asteroid belt.
<span>Ultra violent radiation can damage your eyes when looked at directly and can even cause blindness. It also increases you chances of getting cancer, such as melanoma. It can cause people to age prematurely because of damaged skin and it damages DNA.</span>
Without frequent ground fires to clear out dead brush, a woodland becomes more susceptible to catastrophic wildfires and forest fires that can completely destroy the forest.
However, large forest fires are a natural phenomenon that occur less frequently than small ones.
1) One reason why deforestation is occuring because people need wood from trees to build things, therefore, leading them to cuting countless of trees.
2) One environmental problem that results from widespread deforestation is that the carbon dioxide they would normally use remains in the atmosphere, therefore, promoting erosion.
3) One way to lessen the effects of deforestation is by re-planting the cut-down trees and by cutting down less trees.
This was my answer from the same question that you asked before
I hope it helps though :)