All animals have a system for exchanging carbon dioxide and oxygen with their surroundings. What do all of these systems have in common?

A. All involve the active transport of gases across membranes.
B. All include airways, such as the trachea, that carry air to the mouth.
C. All involve gas diffusion across moist, selectively permeable membranes.
D. All involve organs or tissues that are dedicated to gas exchange and fulfill no other functions.

Organisms are classified, or grouped into categories, based on similarities in their characteristics and/or evolutionary relationships. the study of how organisms are classified is known as

Which of the following types of stars is most likely to end up as a supernova? in graph a, the curve peaks at 800 nm, in the red section of the visible light spectrum. in graph b, the curve peaks at 550 nm, in the green section of the visible light spectrum. in graph c, the curve peaks at 450 nm, in the blue section of the visible light spectrum. in graph d, the curve peaks at 300 nm, in the violet section of the visible light spectrum. a b c d

How did alexander fleming’s research solve a societal problem? he developed ways to treat inherited diseases. he advocated for regular hand washing to kill germs. he discovered a new type of medicine that could treat infections. he discovered the cause of mad cow disease, an emerging disease.