Which statements best describe natural selection? Check all that apply.

a. Populations must have genetic variation.
b. Genetic mutations do not produce advantageous traits.
c. Natural selection occurs when the environment changes.
d. Evolution works independently of natural selection.
e. Organisms best suited for the environment survive and reproduce.

1) a child holds two dogs on two separate leads. the dogs are pulling in different directions. one is pulling a force of 20n north and one is pulling 15n eastwards. calculate the resultant force on the child. state the direction. (use the parallelogram of forces) 2) a force of 20n acts horizontally on an object. a second force of 5n acts at 60 degrees to the first one. calculate the resultant force. worth 20 points, need answers asap with method you x