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Sati [7]
4 years ago
11

When did oxygen levels start to decline from 35 percent down to today's levels during what period

Biology
2 answers:
rosijanka [135]4 years ago
4 0

about 95 million years ago, during the Carboniferous Period

Anettt [7]4 years ago
4 0

Answer:

During Carboniferous period, part of the late Paleozoic era.

Explanation:

In the geological story oxygen levels have been relatively stable for the las 200 million of years, but 300 million ago there was a dramatic spike in Oxygen levels until 35% in the Carboniferous , next it plunged in 15 percent in the Triassic, 100 million years later. The growth of the forests removed huge amounts of carbon dioxide from the atmosphere, leading to a surplus of oxygen. The higher oxygen concentration is related with the presence of larger bodies in reptile and insects.

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During which stage of meiosis does crossing-over occur?
Delicious77 [7]

Answer:

Prophase I

Explanation:

Meiosis is the cellular division that produces the gametes and results in 4 haploid cells. Since these cells will go on to become the offspring, it's important for genetic variation.

Crossing-over is one contribution of genetic variation because it is where the homologous chromosomes exchange parts of their genes. In meiosis, it occurs in Prophase I.

Hope this helps!

7 0
3 years ago
HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
lesantik [10]

Answer:

here!!

Explanation:

oxygen = exocytosis

water molecules = osmosis

charged amino acid = simple diffusion

calcium move from low concentration to high concentration = active transport

protein from the Golgi apparatus = carrier protein

8 0
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maria [59]
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sergiy2304 [10]

Answer:

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