19. What function does the limb serve in each animal? How are the limb bones of the four animals similar? Based on these similaritieswhat can be inferred about the evolution of the four animals ?

Fredrick griffith made a scientific discovery in 1928

How do the sperm cells get from the stigma to the ovules? a. they slide down the petals to the bottom of the flower. b. they travel through pollen tubes. c. they travel along filaments. d. insects carry the sperm cells from the stigma to the ovules.

When is your breathing likely to speed up? a. when your white blood cells increase b. when your cells need more energy c. when your heart cells need more carbon dioxide d. when your blood cells have too much oxygen