Basically all the basic and derived SI units. More information here: http://en.wikipedia.org/wiki/SI_units#Units
Almost all scientists use metric units for scientific measurements.
Yes, it is recommended because the SI-units are based on the metric system.
Because the metric system uses units of 10's to measure which makes things simple.
They are used a lot in science. However, the metric units are also used in daily life, in most countries - with the notable exception of the United States.In some cases, non-metric (non-SI) units are also used; for example, it is customary to use degrees Celsius for temperature (instead of Kelvin); or to use time units other than seconds (such as minutes, days, years) for time.
base on what you measure to use the metric units.
How do you change metric units?
I use metric units, such as meters, kilograms, and liters for measurements.
You use conversion factors.
Oh yes, scientists only use metric SI units.
Metric units of measurement are more fun to say.
What metric unit would you use to measure a computer keyboard
Yes, seconds are a metric unit. They are part of the International System of Units (SI) and are used to measure time.