Which best explains why we are able to accelerate forward when starting to run? A) The runner's upper body quickly leans forward, causing the entire body to begin accelerating forward. B) As one leg moves backward, it provides an opposite force for the other foot to move forward. C) The foot not touching the ground propels the entire body as it swings forward. D) The striking foot pushes backward against the ground. The friction with the ground provides an equal and opposite force forward.

Determine the maximum r-value of the polar equation r =3+3 cos 0

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron

1. when conducting a test on what kind of music increases the growth of plants, all of the following would fail to meet to fair test standard except (1 point) using different kinds of plants. giving some plants more water than others. exposing the plants to different types of music. using nutrient-rich soil for one and lesser soil for others. 2. engineering uses scientific thinking to solve real-world problems. (1 point) true false 3. what does it mean to test a hypothesis? (1 point) pass a quiz on other scientists’ results analyze only the results from scientific sources not make assumptions about how an experiment will turn out see if the results of an experiment are what the scientist predicted