Mia has an investment that is worth $12,000 after 4 years. If the initial investment was $8,000, what is the annual simple interest rate?

12.5 %

Explanation:

Hi, to answer this question we have to apply the simple interest formula:  

I = p x r x t  

Where:  

I = interest (investment after interests - principal; 12000-8000=4000)

P = Principal Amount (initial invest)  

r = Interest Rate (decimal form)  

t= time  

Replacing with the values given  

4,000= 8,000 (x) 4

Solving for x :

4,000= 32,000x

4,000/ 32,000 =x

x= 0.125

Since the interest rate is in decimal form, we have to multiply it by 100 to obtain the percentage.

0.125 x 100 = 12.5 %

Feel free to ask for more if needed or if you did not understand something.  

ans.

heterothermic organisms include those organisms that can switch between homeothermic (having body temperature higher than environment) and poikilothermic (having variation in internal body temperature) strategies.

some migratory birds show heterothermy as they decrease their metabolic rate during cold nights to keep their body temperature low. drop in metabolic rate allows increase in production efficiency of birds that reduces the internal body temperature to make it equal to external cold temperature during cold nights.

thus, the correct answer is 'birds allow their temperature drop in order to increase their production efficiency.'