The enzyme found in stem cells and cancer cells that allows these cells to never enter replicative senescence is:

The “ecological footprint” left by a citizen of a developed nation is about four times larger than that left by a citizen of a developing nation. why is this the case?

What class of levers is shown in this image?

Molecules like glucose and amino acids are not lipid soluble, so cannot cross the cell membrane by simple diffusion. instead, they are shuttled across by carrier proteins in the membrane from high to low concentration. does this process require energy from the cell? this is an example of what type of molecular movement?