Answer:
I, II, III
Explanation:
A threshold stimulus is a stimulus that is capable to produce a response in excitable tissues such as neurons and muscle fibers. At threshold potential, the outward movement of K+ and inward movement of Na+ become equal to each other. When the potential exceeds the threshold potential, more and more Na+ enter the cell to depolarize it and to allow the opening of Na+ channels. Therefore, to fire an action potential, the threshold must be exceeded.
Conduction of action potential is all or none phenomenon which means that either it occurs or it does not occur. As an impulse is passed by each successive part of an exon, it enters the refractory period during which there is no conduction of nerve impulse. It ensures the one-way conduction of impulse from the cell body to the axon terminal only.
Answer: alpha
Explanation: Alpha particles are fast moving streams of positively charged particles that are shown to be Helium nuclei. They have a mass
number of 4 and an atomic number of 2 and a charge of +2. Alpha particles are represented as 4He2. When 238U92 becomes 234Th90, it emitted a helium nucleus 4He2. The equation for the decay is 238U92 ---> 234Th90 + 4He2.
Answer: A
Explanation:
Karyotypes can be used to screen for and confirm chromosomal abnormalities such as Down's syndrome, and there are several different types of abnormalities which may be detected.
Answer:
The process by which volcanoes vent water vapor, carbon dioxide, nitrogen, and other substances is called outgassing.
Under a microscope, gram-positive bacteria (when dyed with the gram stain) appear in purple-colored structures due to the peptidoglycan cell wall.
<h3>What are gram-positive bacteria?</h3>
Gram-positive bacteria are microorganisms (bacteria) that may be colored with crystal violet stain due to the presence of a peptidoglycan-based cell wall.
In conclusion, under a microscope, gram-positive bacteria (when dyed with the gram stain) appear purple-colored structures due to the peptidoglycan cell wall.
Learn more about gram-positive bacteria here:
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