Why is the human heart not considered to be a living organism? a. it cannot complete photosynthesis. b. it cannot reproduce itself. c. it is not made of cells. d. it does not require oxygen.

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.

What are tissues? a groups of tissues that work together b basic units of structure and function c groups of cells that perform the same function d multiple organs that perform a major function

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?