When an object has its motion changed, the cause is generally .
A.
an external force
B.
an internal force
C.
an existential force
D.
an interval force

Please select the best answer from the choices provided.

A
B
C
D

[120 total points] (public health) in one of the largest human experiments ever conducted, in 1954 a randomized controlled trial was run to see whether a vaccine developed by a doctor named jonas salk was effective in preventing paralytic polio. a total of 401,974 children (ages 6–9), chosen to be representative of those who might be susceptible to the disease, were randomized to two groups: 200,745 children (the control group c) were injected with a harmless saline solution (a placebo) and the other 201,229 children (the treatment group t) were injected with salk’s vaccine.what was the point of giving saline solution to the children who didn’t get the vaccine? explain briefly.

Which action is most likely to contribute to a positive self-image?

If scientists are trying to use what they know about hsv to devise a means of protecting other people from being infected, which of the following would have the best chance of lowering the number of new cases of infection? a) vaccinate of all persons with preexisting cases of hsvb) interfere with new viral replication in preexisting cases of hsvc) treat hsv lesions to shorten the breakoutd) educate people about avoiding sources of infection