Answer:
Oxygen levels stay above 15 percent starting 200 million years ago
Explanation:
Atmospheric oxygen levels are related to the evolution on Earth and changes in geochemical cycles that involve climate variations.
The presence of O
2 and evolution of oxygen gave new opportunities to the life on Earth. Oxygen levels in atmosphere have fluctuated between 15% and 35% of atmospheric volume, since the start of the Cambrian period.
So, form the starting 200 million years ago, oxygen level stay above 15 percent and the correct option is "B".
2n-1, is this the answer your trying to find?
They are released into the lymphatic system.
Sodium ions are outside, while potassium ions are inside the neuron.
Answer:
To generate haploid cells.
Explanation:
Previous to the first meiotic division, the genetic material duplicates, giving as a product two diploid cells. Then, these two diploid cells (it means, with chromosome pairs) will divide in the second meiotic division, giving rise to four haploid cells (two each). The gametes, sperm and eggs, should be haploid, so after fertilization they can form a normal, diploid cell.
