Answer: B
Step by Step Explanation:
Get a magnet in a bag (inside out) and move the magnet all over the sand/iron and you can collect all the iron and turn the bag right side out and zip up the bag. Now you have the sand and iron separated and it will be harder to accidentally mix them later.
C.) Newton. & it's S.I. Unit of Force.
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All measurements must have a value and a unit. For example 3 (value) cm (unit). Measurement<span> assigns a numerical value and unit to the characteristics of an object/event, for comparison with other objects or events.</span>
A. pH meter is the instrument which will provide the most direct measure of pH by measuring the hydrogen ion concentration of a solution.
Litmus paper is just a paper which changes color based on whether the solution is an acid or a base. Phenolphthalein is an indicator which changes color based on pH values. And bromthymol blue doesn't tell concentrations, it is just a pH indicator for weak acids and bases.