johannes wants to know whether soil, water, or both are needed for plant growth. he chooses to conduct…

johannes wants to know whether soil, water, or both are needed for plant growth. he chooses to conduct experiments on a willow tree for five years to answer his question. how can his experimental methods be changed to improve his experiment?\nhe needs to ask scientists what they think.\nhe needs to conduct the experiment for a longer period.\nhe needs to use a larger sample size.\nhe needs to test more factors in the environment.

johannes wants to know whether soil, water, or both are needed for plant growth. he chooses to conduct experiments on a willow tree for five years to answer his question. how can his experimental methods be changed to improve his experiment?\nhe needs to ask scientists what they think.\nhe needs to conduct the experiment for a longer period.\nhe needs to use a larger sample size.\nhe needs to test more factors in the environment.

Answer

Brief Explanations:

A single willow - tree is a small sample. A larger sample size reduces the impact of individual - plant variability and gives more reliable results in determining the role of soil and water in plant growth.

Answer:

He needs to use a larger sample size.