A. true b. false. in developed countries, chronic health problems have replaced infectious diseases as the leading killers during the past century.

Although there are a limited number of amino acids many different types of proteins exist because..

The hypothesis of continental drift states that earth's continents, which are located on tectonic plates, move relative to each other. which of the following is true of the movement of the tectonic plates? a. tectonic plates only move once every million years. b. they move at a rate of approximately 5 centimeters per year. c. tectonic plates never move, only the continents located on them do. d. their movements are very rapid and occur at random times.

What type of organism is a one-celled organism that functions as a single unit? a. bi-celled b. single-celled c. pre-celled d. multi-celled