The answer is A, 'a mammal' because it goes with the copulative verb 'to be', i. e., 'is'.
I would recommend b. cause the moon does help tides
u can use con doms to stop it.
The pH of an amino acid is determined by the nature of the side chains of that amino acid. If the side chain of an amino acid contains amine functional group the amino acid will be basic. The acidic amino acids are acidic because they have carboxylic acid functional groups at their side chain.

The nephron loops of the juxtamedullary nephrons are surrounded by a looping, ladder-like blood vessel called the

The nephron loops of the juxtamedullary nephrons are surrounded by a looping, ladder-like blood vessel called the Peritubular Capillary network
This network is formed by the Efferent artiole to absorb the non waste martial which is flown out in the ultrafiltration of Glomerular capsule .