Which suffix indicates "increased" or "excessive"?

The suffix that indicates "increased" or "excessive" is indeed -osis. This suffix is commonly used in medical terminology to denote a condition characterized by an abnormal increase in a biological process. For example, "neurosis" refers to an excessive or abnormal condition of the mind, and "cyanosis" signifies an excessive condition of the skin resulting in a bluish discoloration due to insufficient oxygen.

The other suffixes have different meanings. -rhexis refers to rupture, -itis indicates inflammation, and -oid means resembling or like. Understanding these distinctions is crucial in mastering medical terminology, as they provide vital information about the conditions or processes being described.