Answer:
A
Explanation:
Today, the atmosphere holds about 21 per cent oxygen. ... When the first simple organisms appeared in the oceans more than 3.5 billion years ago, the atmosphere was mostly nitrogen, hydrogen, water vapor, and carbon dioxide
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.
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Answer:
The correct option is B <em>Pressure-sensitive baroreceptors uses tonic receptors which adapt slowly to the stimulus</em>
Explanation:
a. The thalamus receives stimulus from all of the five senses (sight, smell, taste, hear, touch). FALSE. Olfactory information is not sent to the thalamus for its process. The rest is.
b. Pressure-sensitive baroreceptors uses tonic receptors which adapt slowly to the stimulus. TRUE. Among the different types of tonic receptors, we may find baroreceptors, irritation receptors, tactile receptors, and proprioceptors. Tonic receptors characterize by their slow adaptation to the stimulus. The first discharge is maximal when the stimulus is received and then it progressively decreases. They send a continuous signal to the CNS.
c. The three layers that the retina is made of: photoreceptors, bipolar cells, rod cells. FALSE. There are in fact three layers in the retina: photoreceptors, bipolar cells, and ganglion cell layers. NOT rod cells.
d. The sense of smell uses phasic receptors which continuously fire as long as the stimulus is present. FALSE. Olfactive sense uses phasic receptors, but not continuously. These receptors shoot when they receive the stimulus, and then cease if the stimulus keeps constant.