Purines have ring(s), (each) containing nitrogen(s), whereas pyrimidines have ring(s), (each) containing nitrogens.

a) 1; 1; 1; 1
b) 1; 2; 1; 2
c) 2; 1; 1; 2
d) 2; 2; 1; 1
e) 2; 2; 1; 2

E

Explanation: Purines are nitrogenous bases that contains a two-ring carbon structure, with Adenine and Guanine as nitrogenous bases. while pyrimidines has a one-ring carbon structure with Cytosine and Thymine as its nitrogenous base.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.