Answer:
Interactions versus interdependence
Interaction is basically the effect of one thing on another. Biologically, it is the effect of an organism on another organism (vice-versa). This can be between organisms of the same species or different. It can also be the effect of an abiotic factor on an organism. It can be something short term or long term.
Observing versus experimenting
In terms of approach, observing is done using the senses. Observations are done through sense of sight, sense of smell, sense of taste, sense of hearing, and/or sense of touch. Observing as an approach is done without any manupitlation of variables. Changes are noted but are not caused by the observer, so everything that changes is affected by things in the natural environment of the subjects.
Experimenting is another approach where something is manipulated by the observer or experimenter. Observation is also done here, but the key difference is the experimenter is involved. The changes done by the experimenter is usually done to determine if the variable they are testing has an effect on their subject or on what they are testing on.