Physical change as no new substance is created
Answer:
Wings
Explanation:
The most unique feature among phylum Arthropoda is that some of its members have wings. No other invertebrate has winged species!
Making rough estimate of physical quantities is useful because it allow us to have an idea of how big or small a quantity is, it gives us the near result of the real quantity a matter contains. The approximate quantity obtained will give us information about the size of the quantity.
If a HYPOTHESIS is wrong scientists come up with a conclusion, the hypothesis doesn't matter for the result. It is just an educated guess based on the results they expect our hope the achieve.