A student set up an experiment to show the effect of light color on photosynthesis in Elodea plants. She filled two test tubes with distilled water and placed a piece of Elodea in each of the tubes. She added a drop of phenol red, which turns red in a basic solution and yellow in an acidic solution. She blew in each tube before placing the volumeters on the top of the tube. Why did she blow into the tube? Multiple Choice

1) to add oxygen to the tube

2) to add carbon dioxide to the tube

3) to add carbohydrates to the tube

4) to add sodium bicarbonate to the tube

In the united states there are strict fishing seasons and limits, but not all countries enforce similar laws. in bangladesh there are few if any fishing restrictions. what might be the reason for less restrictions in smaller countries like bangladesh? a) the united states is the only country worried about overfishing. b) the united states wants to limit the supply of fish to increase the price. c) bangladesh and smaller countries have an unlimited supply of fish in their coastal waters. d) small countries, such as bangladesh, are practicing subsistence fishing, taking only the fish needed to survive.