The second. Also, most units that are NOT in common use, i.e., fairly unknown by people who don't work in science or technology; for example units related to electricity such as ampere, watt, henry, volt, ohm, siemens, etc.
The unit of length, meters, belongs to both the US Customary System and the metric system.
The second is a standard unit in both the ancient and modern systems.
The unit that belongs to both the US and metric system is the meter (m) for length measurement.
The only unit that appears in both the modern SI (metric) system and the old fashioned system is the second.
seconds
The fundamental unit that is the same in both the metric system and English system is the unit of mass, which is the pound (lb) in the English system and the kilogram (kg) in the metric system.
No, Foot belongs to the Imperial and US customary units (according to Wikipedia)
The gram is a metric unit of mass.
Meters in the metric system is equal to the unit of length.
(g) grams- is the unit used in the metric system.
There are none. The second, although a unit in the SI system is, strictly speaking, not in the metric system since it is based on 60.
If, by 'metric system', you mean the 'SI system', then there is no base unit for volume. The unit for volume is called a 'derived unit', and it is the cubic metre (m3).