The question provided is not complete as it lacks the group of choices, however the group of choices are given as follows:
A. A contraction fails to occur because an action potential is not generated in the muscle cell.
B. A contraction fails to occur because this toxin directly prevents ion release from intracellular stores.
C. A contraction fails to occur because neurotransmitter release by the motor neuron is blocked at the neuromuscular junction.
D. A contraction fails to occur because this toxin prevents cross bridge formation and thereby directly prevents contraction.
E. C and D are both true
Answer:
The correct answer is option A : A contraction fails to occur because an action potential is not generated in the muscle cell.
Explanation:
A muscle contraction takes place when action potential bring to muscles by nerves, which is traveled with the help of motor neuron and imitated the muscle contraction.
Acetylcholine or Ach is a chemical messenger to bring the nerve impulses between a nerve and a muscle. If the receptor is block with applying toxin muscle will not contract as ACh will not be able to propagate the nerve impulse to the muscle so there will be no action potential.
The correct answer is option A : A contraction fails to occur because an action potential is not generated in the muscle cell.
Euglenas are heterotrophic.
Hererophic (must consume food) and autotrophic (can make its own food).
Answer:
Option (d).
Explanation:
DNA is the genetic material of all the organism except some viruses. DNA is composed of nitrogenous base, deoxyribose pentose sugar and the phosphate group.
DNA replicatese by semi-conservative mode of replication in which one the daughter DNA consists of one newly synthesized strand and one parental strand. This mode of replication was explained by Messelson and Sthal experiment. The cells from 15N medium are transferred to 14N medium the band of intermediate density was observed. The daughter DNA consists of one 15N DNA strand and one 14N DNA strnd. This strand undergo replication in the 14N medium. This time one low density DNA band ( contains 14N - 14N DNA strand) and one intermediate density band ( 14N-15N DNA).
Thus, the correct answer is option (d).
Differential reproduction means that some organisms in a population produce more offspring than others.
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Differential reproduction refers to the difference between individuals in a population and how many offspring they are able to leave.The best adapted organisms to a given environment will leave more offspring than those who are not well adapted. Differential reproduction depends on the natural selection.</span>
