Answer:
Smooth muscle
Explanation:
- The smooth muscle is one of the three types of muscle present in the human body and other animals.
- The smooth muscle is called smooth because of its smooth appearance without any striations in its structure.
- The smooth muscle is made of the spindle-shaped cells characterized by a single nucleus.
- The smooth muscle cells are controlled by the autonomic nervous system and therefore is involuntary in its action.
The smooth muscle is present in the hollow organs and propels the substances through these hollow internal passages like in the alimentary canal of the digestive tract and urinary bladder.
Thus, the Smooth muscle is correct.
Answer : Option C) vestigial structures.
Explanation : In the example of whales which is displaying the remnants of the pelvis and femur bones it seems to be the example of vestigial structures.
As vestigial structures are those anatomical feature which no longer seems to have a purpose in the current form of an organism of the given species.
