What describes a period when no ions move through voltage-gated channels?

Under the biological species concept, species are defined as populations that 

Which of the following can lead to the process of speciation? 

One of the effects of a price floor (set above equilibrium price) is

A patient has an order for oral Gantrisin 1 gram. The pharmacy sends you gantrisin tablets that are 500 mg each.  How many tablets will you give the patient?

Evaluate the following summations. Select the correct answer in the dropdown on the right. 

Consider a molecule of DNA.  Which of the following is not true?

A patient has an order for digoxin (Lanoxin) 250 mcg.  The available digoxin tablets are 0.125 mg each.  How many tablets will you administer?

Which of the following best describes the basic structure of a nucleotide?

A patient has an order for nitrostat 0.3 mg.  The available nitrostat tablets are 300 mcg each.  How many tablets will you adminsiter?