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3 years ago

The opening and closing of _____________in your heart create the lub-dub sound and prevent the backflow of blood.

Biology

1 answer:

iVinArrow [24]3 years ago

4 0

Answer:

Heart valves or the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole and the closure of the aortic valve and pulmonary valve at the end of ventricular systole.

Explanation:

The heart tone “lub,” or S1, is caused by the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole.

The heart tone “dub,” or S2 ( a combination of A2 and P2), is caused by the closure of the aortic valve and pulmonary valve at the end of ventricular systole.

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If a stimulus to a neuron is great enough, ________ is reached and an action potential is generated.

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Answer:

If a stimulus to a neuron is great enough, ___threshold_____ is reached and an action potential is generated.

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Where dose mass of a willow tree come from

MA_775_DIABLO [31]

Answer:

So where does the mass come from? The mass of a tree is primarily carbon. The carbon comes from carbon dioxide used during photosynthesis. During photosynthesis, plants convert the sun's energy into chemical energy which is captured within the bonds of carbon molecules built from atmospheric carbon dioxide and water.

Explanation:

Hope it helps! Correct me if I am wrong :>

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How did lucy survive?

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Answer:

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Explanation:

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Chemicals from sea slugs may be useful in:

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Chemicals from sea slugs may be useful in sewage treatment plants.
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3 years ago

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You are examining the phylogenic relationship of a newly discovered plant species (Species 2). You amplify the RUBISCO barcode a

frozen [14]

Answer:

a. Inversion

b. Duplication

Explanation:

Inversion has the name suggest, has to do with a segment of DNA being reversed from end to end.

In this case here,

Inversion is taking place here.

species 1 ATGCAAATTTGGGCCCATGAATGGTTGCAA

species 2 ATGCAAAAATTTTGGTACGCCGAATGGTTGCAA

Therefore, the sequences in bold in species 1 are observed to be reversed end to end in species 2.

Deletion ❌❌

I am sure it's not feasible because deletion entails removal of a few sequences.

It can be seen that species 2 is longer than species 1, which gives another reason why deletion is not feasible too, as no sequences are seen to be deleted.

I believe duplication is feasible since AATT sequences are repeated once.

Our final answer,

inversion and duplication occur here.

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3 years ago