Ohannes 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?

She can plant a plant in one pot full of dirt and not water the plant to see if it is neccesary

Then she can plant a plant in a pot of nothing but water and see if the plant grows well

then she can plant a plant in a pot of both adding water to the soil.

In an expiriment you need to change the vairables to see if the results change,and,then reocrd your results.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex