What chemical that is released by the brain makes a person feel good?

Which of the following will not cause mass extinction? a. drastic change is weather b. geological change c. both a and b d. none of the above

Sarah and john are having a discussion on genetic diversity. sarah believes that it happen over a long period of time. john it happens immediately. who is correct? a. sarah is correct because genetic diversity occurs over a long period of time. b. john is correct because genetic diversity occurs immediately. c. both are correct because genetic variation can occur or long period of time. d. neither are correct because genetic diversity occurs over any period of time

What property of water provides for appropriate sugar, salt, and amino acid levels to be present and carried in the blood of animals to be delivered to cells