The answer is A. Apicomplexa.
I believe that on the Naive B-cell the antibodies exist as transmembrane proteins. A naive b-cell is a type of b-cell that has not been exposed to an antigen. When exposed it becomes either a memory B cell or a plasma cell that secrete antibodies specific to the antigen that was originally bound.
Answer:
It is the varying chemical structure and properties of the R-group that make the amino acids different from one another. About 9 amino acids have non-polar R-groups and are relatively hydrophobic. Another 6 amino acids have strongly polar R-groups which readily attract water molecules.
If I'm not mistaken, it leaves through the osculum which is a cavity located on the upper part of a sponge.
Sponges feed through a process called filtration, which means that they filter the water in search of nutrients. And after they collect everything they need from the water, they need to let it out somehow; through the osculum.
Hope it helped,
BioTeacher101
