12. The ability of Carbon to form up to 4 bonds is important to living organisms in that it allows Carbon to A. bond only with Hydrogen and Oxygen.
B. decay into Boron.
C. build quadruple bonds.
D. form rings and chains.

D, form rings and chaines i think

Explanation:

This allows the Carbon to form long chians with elements such as hydrogen and phosphorus, etc, used some info from this site

https://courses.lumenlearning.com/wm-nmbiology1/chapter/carbon-and-carbon-bonding/

if my answer helps please mark as brainliest.

meiosis is the first to occur after the nuclei of opposite of opposite mating types fuse

the endomembrane system i think