proteins called ___ from channels, or tunnels, through the cell membrane to allow some molecules to pass into the cell?

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.

because it travels in smaller waves then all other colors, causing it to be the most visible color

the flagellates share a facultative mutualist association with termites. mutualism is a biological interaction between individuals of different species, where both benefit from each other. this is called cooperation and it differs from other interactions such as cases of exploitation, such as parasitism, predation. in this interaction called association, both species cooperate and benefit.