He was the first to provide an explanation of evolution supported by evidence.
Answer:
Description
An electron cloud is the region of negative charge surrounding an atomic nucleus that is associated with an atomic orbital. It is defined mathematically, describing a region with a high probability of containing electrons.
Http://highered.mheducation.com/sites/007246268x/student_view0/chapter13/
Because gravity pulls towards the center of the earth evenly in all directions, giving earth a spherical shape.
