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3 years ago

What is the earliest stage of prenatal development at which a rudimentary heart beat can be identified?

Biology

2 answers:

MatroZZZ [7]3 years ago

3 0

Answer:

From the fifth week of pregnancy, its possible to identify the heart beat.

Explanation:

In the third week of pregnancy the heart of the fetus begins to form. For this process, two tubes come together and give rise to five structures: two bulbs, a ventricle, an atrium, and a venous sinus. All this gives rise to the heart tube that, in the fifth week, divides into cavities. This is about the eighth week when the heart is ready.

The heartbeat is noticeable by ultrasound. From the fifth week, on transvaginal ultrasound, depending on the sensitivity of the device, it is possible to hear the heart of the baby. In most such exams you can only hear the baby's heart from 6 and a half weeks.

Elina [12.6K]3 years ago

3 0

Answer:

The germinal stage which begins at conception and last for 2 whole weeks. The embryonic is the second stage and lasts for 6 whole weeks. The last stage is the fetal stage and last two months.

Explanation:

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a scientist is examining the role of an element found in fatd and cabohydrates of living things this element makes up 65% of hum

Shalnov [3]

The question is incomplete as the group of choices are not provided however the correct group of choices are given as follows:

He is studying oxygen, which can also be found in proteins.

He is studying oxygen, which is the most abundant element in the atmosphere.

He is studying nitrogen, which can also be found in proteins.

He is studying nitrogen, which is the most abundant element in the atmosphere.

Answer:

The correct answer is - He is studying oxygen, which can also be found in proteins.

Explanation:

Human body is comprises of various type of molecules and elements such as fats, protein, carbohydrates and many other elements. Carbohydrates and fatty acids are are made up of 3 major elements carbon, hydrogen and oxygen.

Oxygen is an essential element with 65% of all elements found in human body it shows great affinity with proteins. Oxygen binds with hemoglobin then transferred to the through out the body. The oxygen is also one of the elements found in proteins with other elements like nitrogen, hydrogen and carbon.

Thus, the correct answer is - He is studying oxygen, which can also be found in proteins.

7 0

4 years ago

You have gone into the field to take water samples from

timofeeve [1]

Answer:

Lake A: pH = 4.5; Lake B: pH = 7.5

Explanation:

I think that one because if you look on the acid vs base chart acid is from 0-6 and bases are from 8-14 and acids are less toxic, so you would infer that lake A has acid and lake B has bases.

i would have picked the ones closest to 7 ,which is neutral, but I'm not sure that a base can be lower then 7 so I didn't pick answer C

7 0

4 years ago

Read 2 more answers

EPA researchers MOST LIKELY used a_________to view the microorganisms in the stream water samples

Vaselesa [24]

Answer:

Light microphone

Explanation:

Because the microorganisms are counted and classified in order to track changes

8 0

3 years ago

What are the two principle forms of ossification that occur in the development of the skeletal system

In-s [12.5K]

<h2>Answer:</h2>

<em>Ossification is a process in which the mesenchymal cells and cartilages convert to bone during development. it is has two types: Membranous and endochondral ossifications. It occurs in mesenchyme which has formed a membranous sheath (figure 4) .</em>

4 0

3 years ago

Why e-waste is a problem and present one possible way of mitigating the growing e-waste problem.

Ad libitum [116K]

Ewaste is a problem because it contains many hazardous chemicals like mercury, lead and cadmium which could seep in to the soil and eventually to the groundwater. This would lead to contamination of the drinking water. The most important thing to remember would be to separate this type of waste with the others. It would be better if you sell it or give it for reuse. Also, you can send it to a recycler that knows what to do with these wastes.

4 0

3 years ago