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luda_lava [24]
3 years ago
5

_____developed the concept of half-life

Biology
1 answer:
Vera_Pavlovna [14]3 years ago
6 0

Answer:

Ernest Rutherford

Explanation:

The original term, half-life period, dating to Ernest Rutherford's discovery of the principle in 1907, was shortened to half-life in the early 1950's. Rutherford applied the principle of a radioactive element's half-life to studies of age determination of rocks by measuring the decay period of radium to lead-206.

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Some homeostatic imbalances cause a variable that is normally controlled by negative feedback to be abnormally controlled by pos
tigry1 [53]

Answer:

True

Explanation:

Some deviations from normal homeostasis activate the positive feedback loops to control the conditions which are otherwise regulated by negative feedback mechanisms.

For example, the blood levels of respiratory gases and H+ ions are regulated by a negative feedback system via chemoreceptors. The increased partial pressure of carbon dioxide gas and lowered pH or lowered partial pressure of oxygen in the blood are sense by central and peripheral chemoreceptors which in turn activate the neurons of the dorsal respiratory group (DRG).

The activated DRG triggers an increased in the rate and depth of the breathing to facilitate the inhalation of more oxygen and exhalation of CO2 to restore the normal levels.  

However, hypocapnia inactivates the chemoreceptors and does not allow negative feedback to restore the normal CO2 levels in the blood.  

Under such conditions, the positive feedback loop stimulates the DRG neurons more strongly in response to the increased partial pressure of CO2 above the normal levels than when the partial pressure of oxygen falls below the normal level. These dangerously lowered oxygen levels may also cause fainting.  

5 0
3 years ago
A mutation may cause a change in the genotype of a trait? <br><br> True or false
AnnyKZ [126]

Answer:

true

Explanation:

mutations deal with chromosomal changes, and while they might not always be reflected in the phenotype.. the genotype does change

6 0
2 years ago
Why is it important to predict evolutionary responses of a population?
Elden [556K]

Answer:

Because it help us to maintain biodiversity of our planet.

Explanation:

3 0
3 years ago
In 1665, a scientist named Robert Hooke examined a thin piece of cork through a microscope. The drawing below represents what he
-Dominant- [34]

The Englishman Robert Hooke (18th July 1635 - 3rd March 1703) was an architect, natural philosopher and brilliant scientist, best known for his law of elasticity (Hooke's law), his book Micrographia, published in 1665 and for first applying the word "cell" to describe the basic unit of life. It is also less well known that there is substantial evidence that Hooke developed the spring watch escapement, independently of and some fifteen years before Huygens, who is credited for this invention. Hooke also is recognised for his work on gravity, and his work as an architect and surveyor.


Hooke's Micrographia

Here, we focus on his pioneering work using the microscope to document observations of a variety of samples in his book Micrographia, published in September 1665.


Hooke began his famed career by initially studying at Wadham College, Oxford, where he worked closely under John Wilkins with other contemporaries, including Thomas Willis and Robert Boyle, for whom he built the vacuum pumps used in Boyle's gas law experiments. He also built some of the earliest telescopes, observing the rotations of Mars and Jupiter, and, based on his observations of fossils, was an early proponent of biological evolution. If that wasn't enough, he investigated the phenomenon of refraction, deducing the wave theory of light, and was the first to suggest that matter expands when heated and that air is made of small particles separated by relatively large distances, yet curiously Robert Hooke is somewhat overlooked in his contributions to science, perhaps as there were many people who wrote of Hooke as a difficult personality, being described as of "cynical temperament" and of "caustic tongue". There were also disputes with fellow scientists, including disputes with Isaac Newton over credit for work on gravitation and the planets. Though it must be remembered that Hooke lived at a time of immense scientific progress and discovery and none of the above diminish Hooke'

7 0
3 years ago
Read 2 more answers
Identify the start and stop codons in the mrna sequence 5'-uauccauggcacuuuaaac-3'. what is the resulting amino acid sequence
sladkih [1.3K]
MRNA is read 5->3
Start codons can vary depending on the cell/organism type although more generally for mRNA it is always: AUG which is always Methionine 

Stop codons for mRNA are:
<span>UAG ("amber") , UAA ("ochre"), <span>UGA ("opal")

</span></span>
<span>5'-uaucc.aug.gca.cuu.uaa.ac-3'

M-A-L
Methionine-Alanine-Leucine
</span>
4 0
2 years ago
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