The messenger RNA sequences are read in groups of three nucleotides are called a- A: Codon
B: Purine
C: Pyrimidine
D: Ribosome

Which statement is true about the cell theory? a) it is well-supported by evidence. b) it is unchangeable and permanent.

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels

What material did the moon come from?