Barbara is conducting an experiment to observe heat flow. She places one piece of metal in a freezer at -18 degrees Celsius (°C) and a second piece of metal in an oven at 200 °C. After 2 hours, she takes the metal pieces out of the freezer and oven and places them both in the same beaker of boiling water for two minutes. Which of the following best describes how some of the heat will initially move in this system?

Identify and describe the three ways that mutations affect organisms.

How does a catalyst increase the speed of a reaction? a. the catalyst eliminates the activated complex stage, allowing products to form immediately. b. the catalyst lowers the energy level of the reactants, making it easier for them to react. c. the catalyst makes it easier for the activated complex to form, lowering the activation energy. d. the catalyst raises the energy level of the products, making the reaction finish sooner. reset next

Who discovered a pattern to the elements in 1869?