4. the digestive system is critical to maintaining a healthy body because

a. the digestive system is the primary way the body obtains oxygen.

b. the digestive system make food taste better.

c. the digestive system collects the nutrients needed by the body.

d..the body expels all of its waste using the digestive system.

15 points come and ! which characteristic describes all bacteria? a rod-shaped b microscopic c multicellular d autotrophic

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?

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is most likely effect on the ecosystem?