Briefly explain why it is difficult to determine the age of our planet.

What function does the limb sever in each animal? how are the limb bones of the four animals similar? based on these similarities what can be inferred about the evolution of the four animals.

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits

Which statement is true for bacteria a. bacteria have complex internal structures b. all bacteria are spiral in shape c. all bacteria cause disease in animals d. bacteria break down some foods