Answer:
The correct answer is - option d.
Explanation:
Myasthenia gravis is an autoimmune condition in which nerve endings are targeted due to the body produces antibodies against receptors of nicotinic acetylcholine which results in less or no functioning of nerve endings of motor neurons mostly.
Options A, B, and C all three conditions are all due to an increase in muscle movement which is not the case as it causes weakness in the muscles due to less functioning in motor end plates.
Answer:
Crossing-over between homologous chromosomes (prophase 1), the random lining of homologous chromosomes (metaphase 1), and random fertilization are the mechanisms involved in genetic variation.
Explanation:
Crossing-over between homologous chromosomes (prophase 1), the random lining of homologous chromosomes (metaphase 1), and random fertilization are the mechanisms involved in genetic variation.
The Crossing-over events occur between two homologous chromosomes in the equatorial plane and make the daughter cells genetically different from the original one. The Chiasma is the position where two homologous chromatids interchange genetic information, giving a place for new genetic material or information to be provided to descendants. After crossing over, homologous chromosomes get separated again.
On the equatorial plane, homologous paired together, randomly aline with their kinetochores facing opposite poles. The random arrangement of tetrads is different in every cell going through the meiosis process. There is no equal alinement between two cells. When tetrads aline in the equatorial plane, there is no predetermined order for each of the homologous chromosomes of each tetrad to face one of the poles and then migrate to it while separating. Chromosomes of the homologous pair arrange to face any of the poles to migrate forward to it. Each of the chromosomes has two possibilities for orientation at the plane. When the new haploid cells are formed, the number of variations in each cell is also different and depends on the chromosomes that form that cell. The order in the equatorial plane is what introduces variation into the gametes, being almost impossible for two gametes to have the same genetic charge.
Independent assortment occurs when the alleles from two or more different genes distribute in gametes independently from each other. In other words, a gamete receives an allele from a gene that does not depend on nor influence the allele of another gene in the same gamete. This can only be applied to independent genes. An organism gets only one of the members of the chromatids pair of each parent.
Answer:
The largest population that an environment can support is called its carrying capacity.
A result of convergent evolution are the webbed feet of ducks and frogs.
Explanation:
The evolution of the animals, or rather the development of adaptive features, works in very interesting manner. It is very common in nature that animals that are closely related do not share similar characteristics, or the opposite, animals that are not closely related but share similar characteristics. The later case, is referred to as convergent evolution, where totally different animals have developed the same or very similar characteristics in order to be better suited for their environment.
In this case we have the ducks and frogs, and the webbed feet as shared adaptations, or feature. The ducks are birds, while the frogs are amphibians, and their last common ancestor has lived hundreds of millions of years ago. Despite that, both animals have developed webbed feet, and the reason for this has been that both animals have faced the same challenge, swimming and diving, and the webbed feet help them to be much faster and more agile in the water.
Other examples of convergent evolution (in the present and in the past) are:
- Hyena - Tasmanian devil
- Sandy cat - Fenec fox
- Smilodon - Thylacosmilus
- Bats - Birds
Learn more about the categories of adaptations brainly.com/question/2396978
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Reduce carbon dioxide emissions, pollution, and deforestation
reuse materials rather than throwing them away and needing to create more
recycle materials like metals, paper, and plastics
replace non-biodegradable materials with biodegradable
