*Question 22 If a postsynaptic neuron is stimulated to threshold by a spatial summation this implies that
A) The postsynaptic cell has a lower than normal threshold
B) The postsynaptic cell has many synapses with many presynaptic neurons
C) The postsynaptic cell is slow to repolarize
B) The postsynaptic cell has many voltage gated ions channels

hi~~

i would say that hybridization occurs frequently in nature, because there are many types of hybrids that have occurred naturally, such as the mule (male donkey + female horse)

the species living around the vents are especially good at dispersal.  

deep-sea vent originates on the floor of the ocean when seawater circulates through hot volcanic rocks, usually situated where the new oceanic crust is being produced.  

biological dispersal refers to the movement of species from their location of birth to their site of breeding, or from breeding site to another. similarly, the oceanic dispersal refers to the movement of the species from one land mass to another by sea crossing.  

the answer is c. resource depletion