The root meaning 'killing' is?

• A. Cil
• B. Circum
• C. Chrono
• D. Cide

Answer: (D)

Think about how medical terms are built from roots and suffixes that carry specific meanings. The element that conveys killing is -cide, from Latin caedere meaning to kill. When you see -cide in a word, it signals that the term is about killing or an agent that kills (for example, homicide is the killing of a person, pesticides or bactericides are substances that kill pests or bacteria). The other forms shown—circum meaning around, chrono meaning time—do not express killing. So -cide is the part that means killing.