Some tissues, such as the mucosal surface of the gastrointestinal tract, have cells that are capable of cell division and serve as a reserve source for specialized cells. What term describes these specialized cells?

Stem cells

Explanation:

Stem cells are the cells which can form many types of cell in the body therefore they are considered pluripotent. The stem cells can be of two types on the basis of the stage they are present that is- embryonic stem cell and the adult stem cell.

In the given question, the cells of the gastrointestinal tract which can undergo cell division and form specialised cells are known as stem cells due to their ability to form different cells and mostly they are located in the intestine.

Thus, Stem cell is the correct answer.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!