The table shows the amount of radioactive element remaining in a sample over a period of time. Radioactive Decay Rate
Amount of Radioactive Sample
(grams) Time
(hours)
186.0 0
147.0 7
117.0 14
93.0 21
23.3 63

Part 1: What is the half-life of the element? Explain how you determined this.
Part 2: How long would it take 320 g of the sample to decay to 2.5 grams? Show your work or explain your answer.

What problem would a person have if the nucleic acid in one of his or her cells were damaged?

Match the following vocabulary terms to their definitions. 1. amount of energy required to change 1 gram of material from the solid to the liquid state at its melting point 2. a measure of the kinetic energy of the particles of a substance 3. the amount of heat energy required to raise the temperature of 1 gram of liquid water from 14.5°c to 15.5°c 4. amount of energy required to change 1 gram of material from the liquid to the gaseous state at its boiling point 5. the amount of energy required to change 1 gram of a substance 1°c a. temperature b. latent heat of vaporization c. latent heat of fusion d. calorie e. specific heat

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange