Potassium-40 has a half life of 1.251×billion<span> years</span><span>. To determine the percentage potassium-40 remaining after 3.9 billion years, divide
3.9 by 1.251, = 3.12.
This is the number of times the original amount of potassium-40 reduces by 50%. The remaining percentage is therefore 100%/(3.12 * 2) = 16.03%.</span>
Predator and Prey relationships would have the most effect on an ecosystem's stability because they keep a limit number on the opposing population (ex. rabbit population can only get so high because wolves keep eating them / wolf population can only be so high because there is't enough rabbit to eat)
<span>a. chemicals produced by neurons that function as hormones—neurohormones
b. chemicals that act locally on nearby cells—paracrine factors
c. chemicals secreted by presynaptic terminal—neurotransmiters
d. influences same cell type from which it is secreted—autocrine agent
e. chemical secreted into the blood by specialized cells; travels some distance to target tissues—endocrine hormones</span>
Answer:
d
Explanation:
bc theres a chance it could happen
