Answer:
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Explanation:
4 is the correct answer if it helps you then plzz mark me brainliest
The limitation is that she can't test is on humans for ethical reasons. In order to test this, theoretically, she would need to ask some women to use this cosmetic and compare their fetuses to the fetuses of women who didn't. But this is not likely to be approved by the ethical committee, as causing damage to a fetus is not ethical.
Paper
explanation- it’s more biodegradable
In fish, the heart only has one atrium and one ventricle. The oxygen-depleted blood that returns from the body enters the atrium, and then the ventricle, and is then pumped out to the gills where the blood is oxygenated, and then it continues through the rest of the body.
