A student has a job that pays a wage rate of $10 per hour. The night before an economics exam, the student has set aside four hours to study for the exam, estimating that for each hour spent studying, her grade will rise by 5 points. That night, she gets a call from her employer to come to work for a wage rate of $15 per hour for that night. She decides to work for three hours and earn an extra $45.00. The next day she takes the test and gets a grade of 75. The opportunity cost for her work is

15 extra points

Explanation:

Calculation to determine what The opportunity cost for her work is

Based on the information given if her grade is increase by 5 points for each of the hour she spent studying in which we were as well told that She work for three hours which means that her Opportunity cost for her work will be calculated as:

Opportunity cost for her work =3 hours* 5 points

Opportunity cost for her work=15 extra points

Therefore The opportunity cost for her work is

15 extra points

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.'