Ascientist conducts an experiment to test the effects of light on earthworm activity. which is a variable in this experiment?

Identify the missing parts of the carbon cycle

Is there any solid scientific evidence that humans have been cloned?

The embryos of a bird, a reptile, and a mammal are similar in appearance. how does comparing the physical appearance of embryos of different species support the theory of evolution? a. it shows that these organisms share a common ancestor. b. it provides evidence that these organisms eat the same foods.c. it shows that these organisms share the same habitat.d. it provides evidence that these organisms suffered a genetic mutation.