<u>Answer</u>: option B they have a random gene mutation that affects their fur colour.
<u>Explanation</u> :-
- <em>Variation</em> is the phenomena which occurs in all populations.
- These variations result in slight differences in the phenotypes of individuals .
- These variations only arise due to <em>random mutations </em>that arise in the individuals’ genome and then can be inherited by their offspring.
- There is always a probability of one particular trait to make the individuals survive better in the environment as compared to other trait.
- The individuals having the trait that helps them to survive better in the environment tend to survive more and leave more progeny. This is termed as <em>survival of the fittest</em>.
- Thus, according to the question it can be inferred that the dark fur colour arose due to a <em>random mutation </em>since it is the only source of variation. Since, in the given environmental conditions the mice having the dark fur colour were less susceptible to the predators they are better fitted to survive.
- The dark brown fur coat mice, survive better, leave more progeny and hence, increase their population with time. However, the orginal source of origin of this trait was a random mutation. Had this mutation not occured, the dark coloured fur mice would not have been there.
So, a <em>random gene mutation affecting the fur colour made the dark coloured mice first appear in the population.</em>
Hi there!
The example of the meadowlarks is an example of behavioral isolation. This is because the mating call is a behavior the birds exhibit. This helps the birds to find their correct mate because though the birds look similar, they are not able to produce offspring.
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That would be the Thymus Gland.
The primary hormone that the thyroid gland releases into the bloodstream is thyroxine. It is the inactive form, and organs like the liver and kidneys convert the majority of it into the active form triiodothyronine.
The body's metabolism, cardiac and digestive processes, muscle control, brain growth, and bone maintenance are all significantly regulated by thyroid hormones.
Hypothyroidism refers to the thyroid gland producing too little thyroxine. It could be brought on by autoimmune conditions, inadequate iodine consumption, or the use of specific medications. Sometimes there is no known cause. Untreated throxine before birth or during infancy can result in mental disability and stunted growth because thyroid hormones are crucial for both physical and mental development.
Adult hypothyroidism results in a slower metabolism. It may cause symptoms like weariness, a diminished ability to tolerate cold conditions, a low heart rate, weight gain, decreased appetite, impaired memory, sadness, muscle stiffness, and decreased fertility. For further details, read the article on hypothyroidism.
To learn more about thyroxine, refer: brainly.com/question/15557539
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