What are different interactions that can occur between organisms?

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?

Are the layers of rock above and below the coal older or younger?

Which diagram best represents the chromosomes that would be found in a two new skin cells produced as a result of this process?