Identify two structural features of purines and pyrimidines. Purines contain only three ring nitrogen atoms. contain only two ring nitrogen atoms. contain four ring nitrogen atoms. contain two heterocyclic rings. contain one heterocyclic ring.

1) Purines contain only four ring nitrogen atoms while Pyrimidines contain only two nitrogen ring atoms

2) Purines contain two heterocyclic rings while Pyrimidines contain one heterocyclic ring

Explanation:

Purines and Pyrimidines are two classes of nitrogenous bases that make up nucleic acids. They are both heterocyclic aromatic compounds which contains nitrogen atoms in their structure. Although, they are similar but have distinct features namely:

Purines are ring molecules which consists of four (4) nitrogen atoms in their aromatic structure. They are structures with two heterocyclic rings consisting of five (5) carbon and four (4) nitrogen atoms. Adenine and Guanine are the purines in nature.

On the other hand, Pyrimidines are another ring molecules consisting of two (2) nitrogen atoms in their aromatic structure. Their only ring i.e. 1, is also heterocyclic in nature and contains four (4) carbon and two (2) nitrogen atoms. Cytosine, Thymine and Uracil are the pyrimidines.

1. a host loses nutrients to a parasite

2. a parasite only benefits when the host is alive (cause if the host dies the parasite dies with it )

3. producers to consumers

4. the tapeworm is a parasite

5. they convert energy from the sun (photosynthesis)

6. sunflower-robin (i think im 80% sure)

7. producer

8. consumer

9. prey

10. fresh water snails ( cause the green algea is the producer and the snails are the primary consumers and the small fish consumer so is the big fish)

the correct answer was location c, because earth is tilted away from the sun at this time