The walls of the trachea are surrounded by C-shaped rings of cartilage. What is the purpose of this cartilage? A)
Cartilage adjusts the diameter of the trachea.
B)
Cartilage helps to warm and humidify the air of the trachea.
Cartilage prevent foreign objects from entering the respiratory passages.
D)
Cartilage prevents the collapse or overexpansion of the trachea as
pressure changes in the respiratory passages,

4. multiple crosses were made between true-breeding lines of black and yellow labrador retrievers. all the f1 progeny were black. when these progeny were intercrossed, they produced an f2 consisting of 91 black, 39 yellow and 30 chocolate. a. propose an explanation for the inheritance of coat color in labradors. b. propose a biochemical pathway for coat color determination and indicate how the relevant genes control coat coloration.