19. the pia mater layer in the ventricles is rich in blood vessels that produce
a. keratin.
b. csf. c. new skin.
d. dopamine.

Which beat describes the brain stem

100 points and brainlest its 6th grade work compare the parts of a cell and the cell as a whole to another common nonliving system (i.e., a car, a city,

Aspecies has evolved an asexual mode of reproduction by having offspring develop from unfertilized eggs. which of the following will be true of this species' response to natural selection? there will be more deaths from natural selection because there is no mutation. there will be less genetic variation from recombination and a risk of not adapting quickly to environmental change. the species will increase in numbers because genetic variation is increased. the species will compensate for loss of genetic variation by hybridizing with other species. there will be fewer deaths from natural selection because sexual recombination always leads to extinction.