Homologous structures are structures that are similar in related organisms because they were inherited from a common ancestor. These structures may or may not have the same function in the descendants. They all have the same basic pattern of bones. They inherited this pattern from a common ancestor. However, their forelimbs now have different functions
The thoracic region receive sympathetic innervation from the middle and inferior cervical ganglia.
The cervical sympathetic trunk is the portion of the sympathetic trunk located to the left and right of the cervical spine, this trunk extends from the entrance of the thoracic wall to the base of the skull.
- It is made up of 3 ganglia: the superior ganglia made up of the first 3 cervical ganglia; the middle ganglia made up of the 4th cervical ganglion and the inferior ganglia made up of the last 4 ganglia.
- These ganglia are responsible for the sympathetic innervation of the upper extremities, the viscera of the thoracic cavity and that of the organs of the abdominal cavity.
Therefore, we can conclude that the thoracic sympathetic chain is made up of ganglia that innervate the thoracic region.
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Sound production is also known as phonation, and involves the process of vibrations generated by a combination of respiration, the vocal organ and the vocal tract. The physical structures that birds use are highly similar to that of humans, and the sounds that is generated travels through respired air.
Mushrooms because they dont use photosynthesis
Answer:
D.) Helpful variations allow individuals to survive and reproduce better than members who lack these variations.
Explanation:
Variation is one of among the principles of natural selection.
Variations occur naturally thereby favouring some individual groups over the other.
In the above example, the helpful variations naturally select the parents of the offsprings while the other members of the group are disadvantaged.