What is the primary bio molecule that cells use for energy

b) chemical ( the chemical breakdown of food is accomplished by enzymes. )

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trachea, alveoli, lung capillaries, arteries

i think its both a and b

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers