What have we learned from fossil evidence about evolution? It is an abrupt change.

The process is observable.

It takes place during one lifetime only.

The most complex traits are always selected.

What must be true for natural selection to heppen

Which type of neuron stimulates muscles to contract?

The images show two species of tree frogs in a particular region. the gray tree frogs are adapted to the trees of the woodlands, while the green tree frogs can survive in woodlands or grasslands. the gray frog was abundant in the woodlands. because of climatic changes, most of the trees in the region died, and the woodlands changed to grasslands. in such a case, the . the gray tree frog is closely related to the green tree frog genetically, but they have different mating calls. this suggests that speciation occurred because of .