Are enzymes used up after they do there job

Tall, cone-shaped mountains in which layers of lava alternate with layers of ash are called a. shield volcanoes. b. cinder cone volcanoes. c. composite volcanoes. d. lava plateaus. select the best answer from the choices provided a b c d i need asap

Often, caries will develop in an area of the tooth that's not readily accessible. which cavity preparation form defines this? a. retention b. resistance c. outline d. convenience

What is the difference between how ionic and covalent bonds form