Which statement BEST describes the number of galaxies and stars in the universe? A= Billions of galaxies and millions of stars

B=Billions of galaxies and billions of stars

C= Millions of galaxies and billions of stars

D= Millions of galaxies and millions of stars

19. scientists use meteorites that hit earth to provide evidence of the composition of earth's interior because they hypothesize that

What does polymerase chain reaction (pcr) do? o a. separates dna fragments by size o b. cuts a dna sample into fragments o c. provides an overall picture of a person's chromosomes o d. makes more copies of a sample of dna

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.