Scientists think that algae first evolved approximately 2.7 billion years ago, and soon after this oxygen began to exist in the atmosphere. Photosynthesis by primitive plants and algae released oxygen, which gradually built up in the atmosphere.

Explanation:

3 0

3 years ago

Spanish work please help

irina [24]

Answer:

1: repito

2: compite

3: medimos

4: sirven

5: sirves

6: pide

7: sirve

8: competimos

9: repiten

10: miden

Explanation: :D

3 0

2 years ago

Which spanish letters are the most difficult for Americans? *

Oliga [24]

Answer:it would be hardware store, railroad, Idiosyncrasy

this are the most most difficult words

Explanation:

cause it is

7 0

3 years ago