Ques:Q: What substance do the leaves of plants take in from the environment?    Choices:  - oxygen  - hydrogen  - acid rain  - carbon dioxide  A:

Ans:carbon dioxide
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Ques:Q: The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back. it serves to protect the brain, spinal cord, heart, and what else?    Choices:  - ovaries  - knees  - intestines  - lungs  A:

Ans:lungs
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Ques:Q: Fish have a circulatory system with a two-chambered what?    Choices:  - brain  - lung  - stomach  - heart  A:

Ans:heart
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Ques:Q: What can be thought of as the most biologically productive regions on earth?    Choices:  - swamps  - forests  - coasts  - estuaries  A:

Ans: