Why are gills, a heart, and a closed circulatory system a much more efficient way of getting oxygen to all the cells than that of insects?

List two modern organisms that have pentameral symmetry

Research cheetahs on the internet what has contributed to this animal becoming "endangered" or "threatened." what animal you have chosen? -cheetah how long has the animal been endangered or threatened? what has contributed to this animal’s endangered or threatened status? why is it important to save this animal from extinction? after researching and gathering facts, write a 350-word letter from the point of view of an animal rights' activist. be sure to include at least five facts that you learned from your research.

Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas which group of statements best describes all of the materials he is using in the investigation?