B. sexual selection, which alters allele frequencies in the gene pool.
Fish have <span>Eukaryotic cells
</span>
Viruses depend on the host cells that they infect to reproduce. When found outside of host cells, viruses exist as a protein coat etc.
true.
Answer:
D. hotter rock rises and cooler rock sinks.
Explanation:
We know that as we move <u>towards Earth's center</u>, the <u>temperature rises</u>. This rise in temperature causes rocks to melt (magma). The high temperature and melting of rocks <u>decrease the density of material </u>which makes it <u>move upward</u>. By <u>moving upward</u>, the molten rock <u>starts turning solid</u> and becomes <u>denser again</u>. Here, it <u>sinks back due to gravity</u>. This upward and downward movement of rocks due to density and temperature makes a convection cell.
PS: The formation of convection cells in Earth's interior is also the reason for plate tectonics.
There are so many examples for that in different areas, like TPBA experiment carried out in our lab recently.Here's one link: http://www.alfa-chemistry.com/tpba-cas-172285-72-2-item-294462.htm