All of the above points are valid for fossils' contributions in understanding the process of evolution. They allow us to study the ancestry, we can see the homologous organs or structures, if fossils are well-preserved; different fossils can lead us to follow the cycles of the changes that occurred during macroevolutions, and fossils can be used to study different populations which had different body structures for surviving in different environmental conditions.
Answer:
nervous system
Explanation:
the cns oversees every action our body does
<h2>b) option is correct </h2>
Explanation:
- Some bacterial toxins cause disease by altering the activity of G protein, cholera toxin is one of them
- Cholera toxin catalyse ADP ribosylation of Gs and blocks GTPase activity thus Gs GTP become permanently active
- Constitutive activation of Gs protein continuously induce adenylyl cyclase, cytosolic cAMP level rises that leads to activation of protein kinase A (pKA)
- Activated pKA catalyse phosphorylation of two transmembrane proteins of intestinal epithelial cells:
- CFTR cause excessive outflow of Cl- ion and Na+ H+ exchange cause efflux of Na+ ion, both enters in gut and form Na+ Cl-
- Na+Cl- leads to outflow of water from the gut, resulting in diarrhea and dehydration and this condition may cause death of organisms due to loss of water and ions
Exo is spitting big things out. endo is pulling big things in. diffusion is molecules moving from an area of high concentration to an area of low concentration until it is balanced
