Dead Echinoderms are naturally recycled to make which product? a) They are the main ingredient in livestock feed.
b) They are the main ingredient in limestone.
c) They are the main ingredient in toothpaste.
d) They are the main ingredient in collagen.

I'm so confused! If someone could help, it would mean a lot. Thank you and PLEASE no links!

pregnancy happens more and more

eukarya because is is like alche and b is bacteria and d is animals

explanation:

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: