What are two main reasons that prevent cells from growing so large?

answer:a previously unknown mechanism within the cell growth cycle that controls cell size. They made this fundamental finding by studying yeast cells, but it could provide insight to basic human biology as well as diseases such as cancer that thrive by manipulating this mechanism.

Cells of all types seemingly “know” just how large to grow, and when they reach that determined size, they divide into new cells. With no clear answer for what triggers this cellular decision, Jan Skotheim, an associate professor of biology at Stanford University, began searching for the mechanism nearly a decade ago.

Explanation: sorry  if i'm wrong

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

i'd say that the moon rock is about 2.2 billion years old.