Which system and rationale best pairs with the musculoskeletal system to ensure fluid movement of the human body? 1. the digestive system, to obtain the energy that is needed to move the muscles with smooth, coordinated effort 2.the nervous system, to send and receive messages from the brain to move the muscles with smooth, coordinated effort 3.the muscular system, to flex, extend, and rotate the muscles with smooth, coordinated effort 4.the respiratory system, to provide oxygen to the muscles so they will move with smooth, coordinated effort

Which blood cell spend most of their time in the lymphatic system?

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?

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.