1. what is the first line of defense against infection for the human body?
a. white blood cells
b. saliva
c. skin
d. red blood cells

World class speed skaters can skate a 3,000-m course in about 4 minutes. what is their average speed for this course. a. 12.5m/s b. 1.33m/s c. 13.3m/s d. 1.25m/s

Fruit bats in central america eat bananas and other fruits. banana plants rely on bats for pollination. what would be the most likely consequence on the banana crop if fruit bats were eliminated from the area? the banana crop would increase because bats would stop eating the crops. the banana crop would decrease because bats would no longer pollinate the crops. the banana crop would remain constant because bees would replace the bats. the banana crop would remain constant because the plants would adapt using asexual reproduction.

Which type of transport is responsible for oxygen entering into blood cells? a. vesicle b.passive c. facilitated d.active b.passive