The thickness of earth’s crust depends upon

The leopard frog and the pickerel frog are two closely related species. in areas where their ranges overlap, the frogs will remain separate species if they

The distant ancestors of tigers may have had bodies without stripes. use the theory of natural selection to explain how tigers may have evolved to have stripes.

Why are carbon dioxide concentrations expected to increase? a carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase b. carbon dioxide concentrations are expected to increase, because of an increase in agriculture. c.carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. d. all of the above select the best answer from the choices provided mark this and return save and exit next submit submit