8. which of the following body systems does the immune system rely on to provide the first line of defense against pathogens?
a. integumentary system
b. nervous system
c. circulatory system
d. endocrine system

When congress limited the size of washington, dc to 10 square miles, they could not have predicted the growth of the federal bureaucracy. which of the following conditions, do you suppose, is directly related to the inability of the federal city to expand? (select all that apply.)

What feature do the arkansas river valley and the mississippi alluvial plain region have in common

Greg goes to a high school and observes the way students talk to each other. he makes notes on the words used, the atmosphere of the school and the way the students present themselves to each other. this is an example of a( research method.