question below:
Which best describes two organ systems working together to help maintain homeostasis?
OPTIONS:
- The reproductive organs produce sex cells.
- The nerves carry signals from the eye to the brain.
- The bones and muscles of the hand work together to grip a pencil.
- The muscles of the chest tighten to push carbon dioxide out of the lungs.
answer below:
The muscles of the chest tighten to push carbon dioxide out of the lungs.

question below:
Which is a chemical change?
OPTIONS:
- Element 1 is hammered into a thin sheet.
- Element 2 is heated and turns into a liquid.
- Element 3 turns a greenish color as it sits in air.
- Element 4 is ground up into a fine, slippery powder.
answer below:
Element 3 turns a greenish color as it sits in air.

question below:
All animals need food to survive. Immediately after an animal eats food, the food is
OPTIONS:
- stored for later use
- converted into waste
- transported by the bloodstream
- digested into simpler substances
answer below:
digested into simpler substances

question below:
Which cell structure carries out a function for a cell that is similar to the function that bark carries out for a tree?
OPTIONS:
- cell wall
- nucleus
- chloroplast
- mitochondrion
answer below:
cell wall