Question

Mr. Greenjeans wants to know which fertilizer helps grow the biggest pumpkins. He plants three pumpkin seeds of the same variety and then uses three different types of fertilizer on the three seeds. The seeds receive the same amount of fertilizer, water and sunlight. Mr. Greenjeans monitors the pumpkin seeds' growth for three months.

How could Mr. Greenjeans improve his experiment?
A) Mr. Greenjeans needs a control group for comparison.
B) Mr. Greenjeans should use corn and radish seeds as a comparison.
C) Mr. Greenjeans should use three different types of pumpkin seeds.
D) Mr. Greenjeans probably should monitor the pumpkins for a longer period of time.

Answer 1

Mr. Greenjeans needs a control group for comparison.

How do we know that the fertilizer had any impact on growth since Mr. Greenjeans has no control group for comparison? He must know how the pumpkins will grow without any fertilizer as well. The control group gives us a way to compare the experimental groups to help form more valid conclusions.

Answer 2

A)Mr.Greenjeans needs a control group for comparison.
hope this helps