Heartwood. In contrast to sapwood, a term for the dead, clogged xylem cells near the center of a tree. Heartwood is the tree's main column of support.
Answer: I believe the right answer is B) atmospheric nitrogen→bacteria→plants→animals. I'm pretty sure!
Sorry for answering a bit late, hope that helps! :-)
The answer is 2) 12 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
Answer:
breakdown of a substance by bacteria, yeasts, or other microorganisms
Explanation:
