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amm1812
3 years ago
12

Which was the original source of atmospheric oxygen? Question 4 options: autotrophs cooling of Earth’s crust formation of the oc

eans volcanoes
Biology
1 answer:
Nuetrik [128]3 years ago
5 0

Answer:

The answer is autotrophs

Explanation:

During the early days of the Earths life there was no oxygen but there was plenty of CO2 which the autotrophs took and used as food while discarding the excess which was the oxygen.

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Arturiano [62]

Answer:

first and third one

Explanation:

animals need the oxygen they make. and animals eat the plants. if an animal doesnt eat plants it eats somthing that does. sorry for the typos.

3 0
3 years ago
Fish, snakes, and birds are all types of A. spiracles B. vertebrates C. invertebrates D. insects
neonofarm [45]
Vertebrates. they are all chordates, which mean they have a notochord somewhere in their body.

6 0
3 years ago
What is an electron?
Len [333]

Answer: B. The smallest part of an atom

Explanation:

Electrons are the smallest of the three particles that make up atoms. Electrons are found in shells or orbitals that surround the nucleus of an atom. Protons and neutrons are found in the nucleus. They group together in the center of the atom.

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3 years ago
if humans were wiped out and allowed room for a new dominant species, out of all animals listed which one would have the most po
xxTIMURxx [149]

Answer:

the raven

Explanation:

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dolphin - smart but does not have thumbs to make tools and lives in the ocean meaning they have a disadvantage.

raven - intelligent, works with other ravens and sometimes even wolves, and has shown to make tools.

5 0
2 years ago
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3. A.

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Hope this helps
3 0
3 years ago
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