Answer:
Option (B).
Explanation:
Neurons or nerve cell are the basic structural and functional unit of the nervous system. Fibers are the thread like long projection of the nerve cells.
Neurons are classified into three fibers- Group A fibers, B fibers and C fibers. The group C fibers cannot capable of doing the saltatory conduction of the nerve impulse because they are unmyelinated.
Thus, the correct answer is option (B).
<span>I suspect this question should read "How long does a red blood
cell live." A red blood cell lives for between 100 and 120 days. It
takes 7 days for a new red blood cell to develop from stem cells. Stem
cells are similar to base cells. They can also be seen as a general
template from which specialized cells are made. Stem cells can be taken
from a newborn baby's umbilical chord or extracted from an adult blood
donor's blood.</span>
A result of convergent evolution are the webbed feet of ducks and frogs.
Explanation:
The evolution of the animals, or rather the development of adaptive features, works in very interesting manner. It is very common in nature that animals that are closely related do not share similar characteristics, or the opposite, animals that are not closely related but share similar characteristics. The later case, is referred to as convergent evolution, where totally different animals have developed the same or very similar characteristics in order to be better suited for their environment.
In this case we have the ducks and frogs, and the webbed feet as shared adaptations, or feature. The ducks are birds, while the frogs are amphibians, and their last common ancestor has lived hundreds of millions of years ago. Despite that, both animals have developed webbed feet, and the reason for this has been that both animals have faced the same challenge, swimming and diving, and the webbed feet help them to be much faster and more agile in the water.
Other examples of convergent evolution (in the present and in the past) are:
- Hyena - Tasmanian devil
- Sandy cat - Fenec fox
- Smilodon - Thylacosmilus
- Bats - Birds
Learn more about the categories of adaptations brainly.com/question/2396978
#learnwithBrainly
