<span>Nicotinic acetylcholine receptors (nAChR), are <span>ligand-gated ion channels and they can be a Na+, K+ and Ca2+ ion channel. Since nifedipine is a Ca2+ channel blocker (Ca2+ channel antagonist), it might inhibit the response of acetylcholine (if its receptor is Ca channel).</span></span>
Answer: If one is constructing a phylogeny of reptiles using DNA sequence data of birds, mammals, amphibians or fish, the suitable outgroup to be used are mammals due to the time of divergence from other group of organisms.
Explanation: Phylogeny is used to determine evolutionary relationship between items or organisms. A phylogenetic tree is a graphical illustration of phylogenetic relationship. In phylogeny, an outgroup represent an organism that is more distantly related to other group of organisms.
In a phylogenetic tree, outgroup stands alone. It shows that the time of divergence of that particular organism is far from other group of organisms. Outgroup is used to root a tree and sometimes represent a group that is more ancestral on a tree.
It should be noted that differences in the DNA sequences of the organisms under consideration will determine which organism will serve as the outgroup.

<em><u>Nitrogen</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>not</u></em><em><u> </u></em><em><u>a</u></em><em><u> </u></em><em><u>product</u></em><em><u> </u></em><em><u>of</u></em><em><u> </u></em><em><u>photosynthesis</u></em>
Answer:
Uvula
Explanation:
The uvula is a fleshy structure found at the back of the soft palate in the mouth. It is the structure seen hanging at the back of the throat when someone opens his/her mouth and views in the mirror.
<em>The uvula is made up of flexible tissues with the ability to produce saliva. During eating or swallowing of food, the uvula along with the soft palate move to seal off the pharynx in order to prevent food materials from entering the nasal passage.</em>