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forsale [732]
3 years ago
13

The first organisms that performed photosynthesis evolved about 2.2 billion years ago. During the next few million years, their

actions caused which of these events?
A. an increase in oxygen levels, which led to the extinction of many anaerobic organisms
B. a decrease in oxygen levels, which led to the arrival of the first anaerobic organisms
C. an increase in carbon dioxide levels, which led to a warmer climate
D. a decrease in carbon dioxide levels, which led to the first ice age
Biology
1 answer:
frosja888 [35]3 years ago
8 0

Answer:

A

Explanation:

an increase in oxygen levels

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Komok [63]

Answer:

The star is traveling <em>towards</em> the earth.

Explanation:

Space experts arrange stars into groups as per their shading and the composition. This star arrangement framework goes this way: O, B, A, F, G, K, M in which O star is blue and is very hot and <em>M stars are red</em> and the coolest and most basic stars in the Universe.

From the color of the star we can infer that as the star is appearing red it is inferred that the star is an M star and  it is traveling towards the earth.

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4 years ago
Is it easy for breeders to produce mutants?
Eva8 [605]
It depends! If we're talking about something like a cute little Matlipoo, your answer is yes. These are technically considered mutants as they posses characteristics that are not found in either of the original populations (Maltese + Poodles). Not all mutations are bad. Those who survived the bubonic plague are said to have a mutated gene that enabled them to be more resilient against the illness. 

In the case of inbreeding the mutation can prevent offspring from being born by either causing sterility in the parents, or it will cause a miscarriage so the fetus is terminated naturally in the beginning. Sometimes the offspring is still born (deceased at birth), or has debilitating symptoms like in cerebral palsy. So there is a chance that the offspring may never be born, making it impossible for a breeder.

Mutations can also be spontaneous, so a breeder might mean well by selecting two animals from different family trees, but both of the parents could produce mutant offspring together.

This question is pretty vague, you should ask your teacher for clarification.
6 0
3 years ago
In which region is there most likely to be a volcano??
masya89 [10]

Answer:

brainllest if right

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Explanation:

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