What is the unknown substance? Be sure to explain how you know

7th grade question (easy) look at the diagram of the food web. the arrows mean eaten by. what would happen if the number of snakes went down? answer choices are in the image.

Im is in a crowd of people at the mall looking for his girlfriend tammy, who was supposed to meet him for dinner. jim realizes tammy is across the room as he catches a whiff of her overpowering perfume, 'paris #6'. which process explains why jim is able to smell the perfume?

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.