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Kitty [74]
2 years ago
7

What evidence BEST supports the presence of atmospheric oxygen 2.7 billion years ago?

Biology
1 answer:
Serhud [2]2 years ago
7 0

Answer:c

Explanation:layered iron rust in rocks

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Compare the functions of xylem and phloem cells
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Answer:

Xylem transports only minerals and waters from the roots. Phloem transports food materials that are prepared by the green parts of the plants to other parts of the plant. ... Xylem is the dead tissues at maturity, but no cell contents. Phloem is the living tissue, but not with the nucleus.

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If a researcher has a DNA sample with a concentration of 0.6 micrograms per microliter, how many microliters of DNA must be tran
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Answer:

0.325 microliters

Explanation:

1 microgram = 1000 nanograms

DNA sample concentration= 1000 X 0.6 = 600 nanograms / microliters

We need a total of 50 microliter reactions, and the concentration should be 3.9 nanograms per microliter.

So, we need total 50 X 3.9 = 195 nanograms in 50 microliters.

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Both answers C and D are correct, however, answer D makes more sense.

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The class of macromolecule a steroid belongs to is a lipid.
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2 years ago
Scientists studying the passage of genetic materials of the T2 bacteria phage during infection prepared two batches of phages. B
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