I believe it would be to calculate the amount of C-14 atoms left. scientists began to find out how long an object has been decaying, this has to do with half lifes etc. and how long a specific mineral/elements half life is. they use this to calculate how old it is (not an exact age but it's very accurate.)
After gaining electron Chlorine becomes an <em><u>anion.</u></em>
<em><u>and </u></em><em><u>it's</u></em><em><u> </u></em><em><u>symbol</u></em><em><u> </u></em><em><u>is</u></em><em><u>. </u></em>

Hope it helps
Answer and Explanation: The figure below shows the doses of BPA administered to the female mice over time.
An experiment is used to determine cause and effect among variables. When the research is for the impact of a treatment, researchers randomly separate individuals in two groups:
- <em><u>Control</u></em> <em><u>Group</u></em> doesn't receive any treament or a placebo or a treatment whose outcome is already known;
- <em><u>Treatment</u></em> <em><u>Group</u></em> receives the treatment;
For the female mice on the image below, in the First Group is not injected any dosage of BPA, so they are the control group, while the <u>others</u> are <u>treatment group</u>.
The variables in a experiment are classified as independents or dependents:
- <em><u>Independent</u></em> <em><u>Variable</u></em> is the cause;
- <em><u>Dependent</u></em> <em><u>Variable</u></em> is the effect;
For the BPA research, since it is the effect of BPA over time on the mice's cells it is being investigated, <u>dosage</u> of BPA is the <u>independent</u> variable and <em>time</em> is the <em>dependent</em> variable.
Answer: 1: allergic disorders
2. Immunodeficiency disorders
3. Autoimmune disorders
4. Cancers
Coal
Coal is a combustible black rock that is formed from prehistoric plant remains. Coal is formed from the anaerobic decomposition of dead plant matter such as trees, ferns, mosses and other marsh plants that grew on the earth surface over millions of years ago. Coal is composed largely of carbon and is usually burned as a fuel.