Answer:
Option A, oxygen in the atmosphere
Explanation:
The highest level of oxygen reached during this phase of the geological cycle of earth. The oxygen level in Carboniferous period accounted for 35% as compared to 21% of oxygen in the atmosphere in present time.
Due to high oxygen content, the giant and wide varieties of terrestrial animal and plant species evolved. For example – size of insects and carwlies increased, plant became extremely giant, increase in number of tree ferns etc.
Answer:
D
Explanation:
Everything in there pollutes the environment.
Answer:
d.They prevent the two parental strands from coming together again.
Explanation:
During the process of DNA replication, the two DNA strands should be separated from each other to serve as a template. To separate the two DNA strands, the helicase enzyme breaks down the hydrogen bonds between the complementary base pairs of the DNA strands. The process uses ATP as a source of energy.
Due to the presence of complementary base pairs, the separated DNA strands have a tendency to reanneal by the formation of hydrogen bonds. To prevent the reannealing of separated DNA strands, single stranded binding proteins bind to them. Binding to single stranded binding proteins to the separated DNA strands does not allow them to reanneal.
1) Oxygen
2) Carbon
3) Hydrogen (water)
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