How do the body’s exterior lines of defense prevent illness? (7th grade science)

a) they prevent pathogens from entering the body.
b) they make antibodies to protect against new pathogens.
c) they warn the body that pathogens have entered the body.
d) they cause fevers so that the body is too hot for pathogens to survive.

Compare and contrast the adaptations of free-living flatworms and parasitic flatworms

Now it's your turn to investigate human impact around the world. grab your virtual lab coat and put on your environmental science hat. you will be taking a trip around the globe to explore three locations. at each location, you will investigate the cause and effect relationships of deforestation, desertification, and urbanization. you will also gather evidence of how these factors have impacted the environment over time

Idon’t know the answer and i’ve been stuck on it for a while now skskskskks