Question

Biogeochemical cycles are crucial to ecosystem function because
A) they keep the planet warm enough for living things to survive
B) energy flows through ecosystems in one direction only and is eventually dissipated as heat
C) they prevent catastrophic extinctions
D) nutrients and other life-sustaining molecules are in limited supply and must be continually recycled

Answer 1

D) nutrients and other life-sustaining molecules are in limited supply and must be continually recycled is your answer

Answer 2

$\bf\huge\color{red}{ANSWER}$

Biogeochemical cycles are crucial to ecosystem function because nutrients and other life-sustaining molecules are in limited supply and must be continually recycled.