Which of the following amino acids have more than one asymmetric center?

check all that apply.
serine
isoleucine
proline
leucine
tryptophan
arginine
glutamate
threonine
lysine
tyrosine
glycine
alanine
asparagine
phenylalanine
histidine
valine
methionine
glutamine
cysteine
aspartate

What is the empirical formula of vanadium 1 oxide given that 20.38 grams of vandium combines with oxygen to form 23.58 grams of the oxide

How does a sample of helium at 15 degree celsius compare to a sample of helium at 215 k? a) the helium at 15 degrees celsius has a higher average kinetic energy that the sample at 215 k. b) the helium at 15 degrees celsius has lower nuclear energy that the sample at 215 k. c) the helium at 15 degrees celsius has slower- moving atoms that the sample at 215 k. d) the helium at 15 degrees celsius has smaller atoms than the sample at 215 k.

Can anyone answer these questions? ? i need it before 1: 00pm today