Answer: I think it's either C or B? but I could be wrong.
Explanation:
Something that could help: The function of an organ system depends on the integrated activity of its organs.
Answer:
A Gene pool is best described as, all the alleles present in an population.
Explanation:
Answer: D. I, II, III, IV, V, and VI
Explanation:
Oxygen is recquired for cellular respiration and break down nutrients like sugar to create ATP. Organisms from all kingdoms like Bacteria, Archea, Plants, Protists, animals and fungi can use cellular respireation.
Answer: More than 99 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At least a handful of times in the last 500 million years, 75 to more than 90 percent of all species on Earth have disappeared in a geological blink of an eye in catastrophes we call mass extinctions.
Though mass extinctions are deadly events, they open up the planet for new forms of life to emerge. The most studied mass extinction, which marked the boundary between the Cretaceous and Paleogene periods about 66 million years ago, killed off the nonavian dinosaurs and made room for mammals and birds to rapidly diversify