One primary function of setting things fall apart is to paint a portrait of a specific culture
Answer:
Birds can keep themselves warn without any external heat source which is not the case with reptiles and amphibians
Explanation:
Birds are able to generate heat means they are endothermic. They generate heat through various metabolic processes. They have air pockets beneath their feathers to insulate their bodies during cold temperatures. Feathers which are modified reptilian scales help birds to streamline their exterior body and structure feathers in a way that it insulates the body.
So we know that to transport materials in or out of the cell, we need to have access to both the inside and outside of the cell. This would require that the protein be a transmembrane protein that reaches both the inside and the outside of the cell.
So in this case, let's look at pore proteins. These are proteins that cross a membrane and act as a pore for the materials that need to cross the membrane.
One example of a pore protein is an aquaporin. These proteins aid in the transport of water into or out of a cell.
Therefore, the answer to your question is: A) Pore proteins.
