A <em>parasitic relationship is a form of relationship/interaction between two organisms in which one organism (called parasite) lives at the expense of the other organism (called host); causing harm or death to the host</em>.
A hornworm caterpillar feeds on the upper part of tomato plant leaves, causing harm to the plant in the process. Hence, <u>the tomato plant is the host while the hornworm caterpillar is the parasite.</u>
