Most organisms either directly or indirectly use energy from the sun to survive, but not all of them. Plants and some microbes use the energy from the sun to perform photosynthesis.
Diffusion is across a semi-permeable membrane. The larger the membrane, the longer the diffusion takes
Mammals. I am no scientist, but I think that they are closer to mammals due to the fact that they are warm-blooded, and they raise their young. Reptiles are cold blooded and usually leave their offspring to fend for themselves.
A membrane bounded organelle whose main function is to undergo protein synthesis would be the ribosomes. These can be embedded in the endoplasmic reticulum or be freely floating in the cytoplasmic region of the cell.
