How many pulmonary veins return blood to the heart

Which of the following best defines preload

Match the following letter on the diagram with the corresponding number below Capture2.PNG

The valve located between the right atrium and the right ventricle is the 

Cartilage is absent in bronchioles ______________  mm in diameter or less.

Which food crop was primarily grown in the Caribbean and imported North into the British colonies along the triangular trade route? 

The need for which staple crop gave rise to the fight between British and French over disputed lands in the Ohio River Valley.

Increase of colonial taxes by the British was primarily due to the need to pay off debts for the French and Indian War.

Before migrating to the American colonies, many Puritans found refuge for a handful of years in which European country? 

What do we call an arm of private citizens that supplies their own weapons and protects homelands while being set up by local government?