Which of the following is a form of active transport?
a) carrier protein
b) receptor protein
c) sodium-potassium pump

Active transport requires energy when moving molecules against a concentration agent. It requires for specific membrane transport proteins. Only a certain type of protein can move a certain type of substance. 

The three main types of Active Transport are:
1) Sodium-Potassium Pump
2) Endocytosis
3) Exocytosis  

(1)Hoops shadow would be 6 ft (2) model would be 3 cms

Step-by-step explanation:

9 / 3 = 3   3 x 2 = 6 ft

15 / 5 =3    3 x 1 = 3 cm