Q: The enzyme pepsin works only in the presence of what? Choices: - carbohydrates - sodium - oxygen - acid A:
acid

Q: Contour tillage helps slow water run-off and what process that causes topsoil loss? Choices: - water erosion - ice shelf erosion - plate tectonics - soil erosion A:
soil erosion

Q: Q: What is the process of breaking down food into components the body can absorb called? Choices: - absorption - filtration - excretion - digestion A:
A: digestion

Question: Q: What cannot exist between energy levels? Choices: - crystals - protons - cells - electrons A:
Answer: electrons

*Question*
Q: The relationships between groups of different species makes up a ___________. Choices: - species - family - food chain - community A:
**Answer**
community

(Question)
Q: What do vertebrates possess that is made up of repeating bony units? Choices: - notochord - skull - spinal cord - vertebral column A:
(Answer)
vertebral column