Amino acids have similar structures. What part of an amino acid's molecular formula distinguishes the macromolecule from other amino acids? O the R-group
o the amino group
o the carboxyl group
O the nitrogenous base W

Which is it a characteristic of the animal kingdom? a. they include both vertebrates and invertebrates b. their skin is covered with hair or fur c. they are heterotrophs d. they are eukaryotic

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.

The table below shows the number of foot bones in some horse fossils.horse fossil recordhorse fossil number of foot bonesp 19q 17r 24s 13ancient horses had more bones in their foot then present-day horses. the present-day horse has 11 foot bones. what is the correct order of evolution of the horse starting from the youngest fossil? a. q p r s b. s r p q c. s q p r d. r p q s