Natural formation of lead occurs by radioactive decay of uranium and thorium through radon (222Rn). Four stable isotopes are known, 204Pb, 206Pb, 207Pb and 208Pb, the first three of which are used for estimating the ages of rocks. Lead compounds exist mainly in +2 or +4 oxidation states, the former being more common.
No mutations that neither benefit nor harm the organism has no effect on the organism's survival.
Explanation:
The neutral mutations do not cause any effect on the organism they occur. They are called silent point mutations because they do not code for the amino acid change in the proteins.
They have no effect on the organism's survival neither beneficial nor harmful effect.
The neutral mutations do not affect the process of Natural selection.
Answer:
C. Excess nutrients promote the growth of algae
Explanation:
The eutrophication can simply be explained as an over-saturation of the waters with nutrients. This usually happens because of the human activity, with the largest sources that contribute to this being the fecal matter from the farmed animals and the fertilizers used in the agriculture. They are either released into the water directly or manage to reach it on their own by natural means. Once they reach the water they increase the amount of nutrients a lot, and that prompts the growth of the algae. As the algae grow more and more and occupy more and more area, they block the sunlight, so the organisms that use photosynthesis die out. Also, the algae contribute to eliminating the oxygen of the waters, so the fish and the other organisms die out as well, leading to a total collapse of the ecosystem.
