Mark sees an attacker approaching him with a knife. during his reaction, he experi-ences increased energy and a faster heart rate. this is caused most directly by

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons

18. which statement about cancer is true?