What is the purpose of the r group in an amino acid monomer ?

Which of the following is a main difference in cell structure between an onion cell and a human cheek cell? a. an onion cell contains one nucleus, whereas a human cheek cell contains two nuclei. b. an onion cell has a cell wall. c. a human cheek cell contains chloroplasts. d. there is no difference between an onion cell and a human cheek cell. you for your.

Molecular models of two different substances are shown below. in the molecule on the left, the oxygen atom pulls on electrons more strongly than the hydrogen atoms. in the molecule on the right, the two oxygen atoms pull on the shared electrons with the same strength. water molecule, h, o oxygen molecule, oz when the two substances are put in the same container, they do not attract each other. why does this happen? a. they both contain oxygen. b. one is polar and one is nonpolar. c . they are both polar. d. they contain different elements.

Contrast how pollination is different among gymnosperms and angiosperms.