Explanation:
Two important ways by which humans have affected the carbon cycle, especially in recent history, are: 1) the release of carbon dioxide into the atmosphere during the burning of fossil fuels, and 2) the clearing of trees and other plants (deforestation) that absorb carbon dioxide from the atmosphere
1, O because if either shows present it's O.
Answer:the answers are a and d
Explanation:
I did the test sorry if wrong
Helicase "unzips" the two strands of DNA. During DNA replication.
