Charles darwin proposed that evolution by natural selection was the basis for the differences that he saw in similar organisms as he traveled and collected specimens in south america and on the galapagos islands.

Gabriel is at a stage where his body is changing physically; he is growing facial hair and building muscle. he is also just starting to make sperm. what is most likely gabriel’s age? 5 12 17 21

What's the waste product of electrons and pyruvate combining in fermentation?  

The current thought on the structure of the cell membrane is: a. a static phosphate sandwich of lipids b. a fluid-mosaic of phospholipids and proteins c. a bilayer of proteins with static lipid molecules d. an impermeable bilayer of protein molecules e. a static and permeable phospholipid single layer