Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
Directions: Use the information provided and your knowledge of Life Science to answer the following questions. Show all work where necessary.
A student conducted an experiment to see if a popular brand of plant food had any effect on bean plants growing in sand. Ten plants were started from seed. Each seed was planted in a small container filled with sand. Plant food was added to the sand in only five of the containers. All other physical factors were kept the same for all ten plants. The experiment continued for 35 days. The student kept a journal during the experiment. Three of the entries are shown in the table below.
Day | Entry |
|---|---|
15 | During the first 15 days, the plants all looked the same. There was no difference between the plant food group and the other group without plant food. |
30 | Observed the plants today. The five seeds given plant food were all at least 5 cm taller than the group without plant food. They also had at least two more leaves than the group without plant food. Some of the leaves on the group without plant food were yellowish. |
35 | My experiment shows that bean plant growth is increased by adding plant food to sand. |
According to the journal entries, what difference was observed on day 30 between plants grown with plant food and those without?
Using the information from the journal, describe one piece of evidence showing how plant food affected bean plant growth by day 30.
Explain how the yellowish leaves in plants without plant food provide evidence that nutrients are important for healthy plant growth.
Construct an argument supporting the claim made on day 35: Bean plant growth is increased by adding plant food to sand.
Which statement best explains why the two groups appeared the same during the first 15 days?
Describe how the student controlled variables in the investigation. Explain why controlling variables is important for interpreting the results.