The right answer is A) Trisomy
Aberrant karyotypes containing an abnormal number of chromosomes are known in the human species. The best-known (and most common) chromosomal abnormality is trisomy 21, which is responsible for Down syndrome (mongolism). There are others such as Turner syndrome (woman with a single X chromosome) or Klinefelter syndrome (man XXY).
These abnormalities originate from the non-disjunction of the chromosomes of a pair of homologues during metaphase I of meiosis. At the end of division I, a daughter cell contains the two chromosomes of the pair considered and the other cell does not contain a chromosome of this pair. A similar result can be obtained during a bad distribution of chromatids during anaphase II.
After fertilization from a gamete of this type, a trisomy or a monosomy is obtained.
<span>The migration routes of Homo sapiens reveal
that they went through many environmental and physical challenges but adapted
everything much quickly in comparison to the other animals. The evolution
allowed other species also to adopt these changes but it took them a long time
to fit in the new environment, a sub species of a species adopted the new and
the previous one could not, but Homo sapiens invented ways and tools to combat
and evolve much quickly. It included their living, dietary needs, clothing and
much more.</span>
The correct order of steps in a gram staining procedure is:
(4) the specimen is treated with a stain called crystal violet.
(1) iodine is added as a fixative or mordant.
(3) the specimen is flushed with alcohol to dehydrate peptidoglycans and trap the stain.
(2) the specimen is treated with a stain such as safranin or fuchsin (a pink stain)
Gram staining is a common staining technique which helps to classify the bacteria into two categories: Gram positive and Gram negative. Gram positive bacteria appear violet in color and Gram negative bacteria appear to be pink. This color difference appears due to the difference in the bacterial cell walls.
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<span>Bryophytes</span> are more adapted for moist environments. This is due to the fact that they can live in water-filled places with mild temperatures.
Answer:
The nucleus controls and regulates the activities of the cell and carries the genes, structures that contain the hereditary information.
Explanation:
