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

What is it called when plants lose water though their leaves

Blood has traveled from the heart to the toes. which describes the next step of the circulation process?

Astudent reads the following text in a science book: scientific evidence tells us that the cause of earths four seasons is the tilt of earth as it revolves around the sound the student is instructed to illustrate this information in a science book. how will the student illustrate winter in the northern hemisphere? a.earths northern hemisphere will tilt away from the sun. b. earths northern hemisphere will tilt toward the sun. c.earths orbit will be farther away than from the sun d. earths southern hemisphere will tilt away from the sun.