Cardiac muscle and some types of smooth muscle have the ability to contract without any external stimuli. True or False

1 answer:

8 0

True.

Explanation:

Cardiac muscle and some types of smooth muscle have the ability to contract without any external stimuli.

These muscles are called involuntary muscles.

Involuntary muscle are named so because,these muscles are independent of voluntary control and are controlled by our autonomic nervous system.

These are also known as white or smooth muscle.

Examples, muscles of heart, muscles of alimentary canal etc.

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sweet-ann [11.9K]

Answer:

This is due to the event of Speciation that happened for the rodents in Island B but not for the rodents in Island C.

Explanation:

The sub-population of rodents formed in Island B are B1 and B2.
The sub-population of rodents formed in Island C are C1 and C2.
In case of Island B, each of the B1 and B2 sub-populations that got split from each other developed certain mutations that were necessary for them to adapt to the particular diverse environment each of them were exposed to, through the period of 50,000 years. These mutations were so varied that reproductive isolation was generated between them that resulted in each of them to develop into different species.Hence, speciation happens here and B1 and B2 are incapable of inter-breeding.
In case of Island C, each of the C1 and C2 sub-populations that got split might have got exposed to similar environmental change or no environmental change or the environmental change might have been too small to cause drastic change in each of the sub-populations. As a result of this the two sub-populations might have acquired certain mutations to adapt to the environment each of them were exposed to, through a period of 100,000 years. These mutations might not have been too variable or contrasting to cause reproductive isolation between C1 and C2. Hence, no new speciation happens here and C1 and C2 are capable of inter-breeding.