How do specific cell structures and organelles contribute to maintaining homeostasis in the cell?

Homeostasis is a self-regulatory process by which cell maintains its internal environment constant. Plasma membrane plays significant role in in maintaining the homeostasis due to its semi-permeable nature. Cell membrane or plasma membrane is a phospholipid bilayer, it only allows small and non-polar molecules to pass through it. It prevents polar ions or molecules to pass through it. Thus it controls movement of molecules and maintaining the constant internal environment.  

the core of the sun is so hot and there is so much pressure, nuclear fusion takes place, hydrogen is changed to helium. nuclear fusion creates heat and photons. when the heat reaches the earth it warms the molecules of the atmosphere, and they warm other molecules and so on.

correct answer is a. and d.