Question

1. explain two ways in which the existence of green algae and land plants affected the early atmosphere.

Explanation:

Green algae and land plants perform photosynthesis. Photosynthesis consumes carbon dioxide (\(CO_2\)) from the atmosphere and releases oxygen (\(O_2\)). So, they increased oxygen levels and decreased carbon dioxide levels in the early atmosphere.

Answer:

1. Increased oxygen (\(O_2\)) levels: Through photosynthesis, they produced \(O_2\) as a by - product.
2. Decreased carbon dioxide (\(CO_2\)) levels: They used \(CO_2\) as a reactant in photosynthesis.