How many significant figures are there in the measurement 64,000 mg? a. 2 b. 3 c. 4 d. 5 (possibly a but idk)

I'm pretty sure that significant figures is just the amount of numbers there is. So, in this case I think the answer would be D. 5

tracks, burrows, eggshells, nests, tooth marks, or gastroliths

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.