Ben is doing a lab with baking soda and vinegar. He noticed that a chemical reaction took place when he mixed the two substances together. Which of
the following BEST indicates (shows) a chemical reaction took place?
A. a change in mass
B. a change in color
C. the production of a gas and bubbles

this allows people to make the best decision or pursue the best option. when alternatives are weighed using their advantages and disadvantages, the option whose disadvantages outweigh the advantages (based on a qualitative or quantitative analysis) are shunned while those whose advantages outweigh their disadvantages are pursued.  

i think they are all correct

explanation:

they seem good

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg