The first line of defense against pathogens includes:
a. inflammation and phagocytosis
b. the skin and mucous membranes
c. interferon and complement
d. fever and lysozyme
e. skin and phagocytosis

*will mark brainliest for first correct answer* which of the following is most likely to affect the biodiversity of a park ecosystem? a. less rain than usual for several months b. ongoing pollution from a nearby factory c. park rangers plant a new type of tree d. disease wipes out an entire population

Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?

Radiometric dating is used to tell the absolute age of materials by studying the decay rate of radioactive isotopes. the decay rates of isotopes are constant and are expressed as .