The ounce.
It is customary to use the kilogram - though that is technically not a weight, but a mass.
a ruler
The appropriate scale for the measurement of the weight of an earring would the milligram. this is because the weight of an earring is so small that it would be difficult to determine it s weight while reading on a bigger scale like the kilogram.
The units grams would be a good choice.
In most countries, it is customary to measure that in liters.
the metric system
millimetres
The best unit for measuring the length of a pencil is inches.
The best unit to measure the weight of strawberry is kilogram.
inches or centimeters
pounds or kilograms
If you have to measure the pencil to a couple decimal places i would suggest a micrometer and a dial caliper.