Investigation, Results, and Conclusions

A curious person set out to determine what variables affect the germination of seeds.

The person took two plastic bags, two paper towels, dropped five drops of water on the surface of each paper towel, folded each damp paper towel so they fit inside the plastic bags, placed one inside each plastic bag, and spread twenty grass seeds on the surface of each paper towel so they could be viewed through the plastic bags. One bag was placed inside a black opaque cardboard envelop so that no light could enter and the other was not. Then both were placed on a table with a light source connected to a timer that turned on at 6:00 AM and shut off at 8:00 PM. During the time the light was on the temperature was between 80 and 90 degrees. During the experiment the seeds in both bags germinated at a very similar rate and at the end there were 19 seeds germinated in the plastic bag put into the black envelop (dark) and 18 germinated in the plastic bag set in the light.

Directions: Based on the data from this experiment, which of the following is a valid conclusion.

1. moisture is necessary for seeds to germinate.
2. heat is necessary for seeds to germinate.
3. plastic bags are necessary for seeds to germinate
4. light is not necessary for seeds to germinate.
5. light is not necessary for grass seeds to germinate.
   

Explain your choices.