Such information is valid when A. it is not biased.
There is no bias in science - the results are either correct or incorrect; personal opinions have nothing to do with that. B is incorrect because the point of experiments is that they can be repeated to achieve the same results. C and D are likewise incorrect as primary sources are important, and you can share the results with others if you want to.
Answer:
B) Tommy had a positive acceleration between noon and 12:30 pm.
Explanation:
Acceleration is defined as the rate of change of velocity:

where
v is the final velocity
u is the initial velocity
t is the time
In the problem,
- At noon, Tommy is walking at a velocity of 4 mi/h
- At 12.30 pm, Tommy is walking at a velocity of 6 mi/h
- A time of half an hour (0.5 h) passed between the two moments
So Tommy's acceleration is

and the acceleration is positive, since the velocity has increased.
Body Fossils and Trace Fossils.
Hope I helped and good luck with school. Bye!