What are four elements that cycle through ecosystems, and why are they important?

Use this diagram of an animal cell to answer the question. where does the first stage of cellular respiration occur? w x y z

Liquid water turns into water vapor at which step in the water cycle? a. precipitation o b. water run off c. evaporation d. condensation

Living cells cannot use heat to provide the activation energy for biochemical reactions because which choice(s) complete the sentence correctly? a) answer choice ii. eliminate b) answer choices ii and iv. c) answer choice iii and iv. d) all answers can complete the sentence.