Agroup of organs working together to perform a certain function is a(n)
a. organ system
c. organ
b. tissue
d. organism

it is organ system

Explanation: all it is just process of elimination because a tissue is a group of cells working together not organs and an organism is like an animal or human not an organ and organ is not it because it is a group of them wwhy would they call it an organ if it is in a group of the thing so there u go hope this helps pls read this :)

the answer is b.) hydrogen bonds between bases.

b. to discover aspects of the natural world.

hopefully i .