Q: Flatworms have a concentration of nerve tissue in the head end, which was a major step in the evolution of what organ? Choices: - liver - heart - kidney - brain A:
brain

Q: During the first several weeks of development, the cells of the endometrium nourish what? Choices: - egg - nucleus - uterus - embryo A:
embryo

Q: Q: Groundwater dissolves minerals and rocks into what? Choices: - gravel - sand - grit - ions A:
A: ions

Question: Q: How is energy expressed when it is released in a chemical reaction? Choices: - as an equation - as a percentage - as a positive number - as negative number A:
Answer: as negative number

*Question*
Q: Why do birds need a light-weight body? Choices: - for cooling - water flotation - food shortages - to stay aloft A:
**Answer**
to stay aloft

Q: Q: If an air mass forms over an ocean it is called what type of air mass? Choices: - cumulus - hurricane - tropical - maritime A:
A: maritime