The fear of what animal is known as ‘arachnophobia’?

the correct answer is self-renewal.  

the hemopoietic stem cells, found in the red bone marrow, is a usual example of adults stem cells. these stem cells, divide into different kind of blood cells. the bone marrow also comprises a second kind of adult stem cell called mesenchymal or stromal stem cell. the adult stem cells have also been witnessed in various other kinds of tissues like skeletal muscle, brain, skin, blood vessels, heart, and the teeth.  

these adult stem cells possess the tendency to differentiate into other kinds of cells, and can also differentiate in self-renewal to generate more of the similar kind of stem cells.  

self-renewal refers to the procedure by which the differentiation of stem cells takes place to produce more stem cells, continuing the pool of stem cells all through the life. self-renewal is considered as the differentiation with the sustenance of the undifferentiated state.  

i believe it is b but im not sure

answer:

the egg contains both food and mitochondria in addition to its vital dna, thats why it is much larger. the sperm cell has to be much smaller than the egg cell, because it is the one that swims. if a sperm cell were as big as an egg, it would not be able to move very fast nor very far.