tons
Kilograms would be used to measure the mass of an elephant.
You would use the unit of measure called "kilograms" to measure the mass of an elephant.
it would be the same wherever you are
No, the mass of the elephant will never change, but on the moon the elephant would weigh less. Weight is the affect of gravitation wich is the attraction of two bodies that have mass. The mass of the moon is smaller then that of the earth so the gravitational pull would be less.
A ton for a rough and ready measure. A tenth of a ton (100 kilograms) if you were a biologist following the elephant's development in more detail.
A very large balance
The mass of an object remains constant regardless of its location in the universe. So, an elephant's mass would be the same on the Moon or Mars as it is on Earth. However, an object's weight, which is the effect of gravity on its mass, would differ on the Moon and Mars due to variations in their gravitational pull.
nothing
Ideally kilograms or tons.
Any of them really. But most would use the kilogram
A five-year-old cat is likely to have a mass close to 3 kilograms. Adult domestic cats typically weigh between 3 to 5 kilograms, making them a suitable comparison. In contrast, an elephant peach and a small feather would weigh significantly less, while an elephant peach can be much heavier depending on its size.
Momentum is the product of the mass and velocity of an object. Since a golf ball has a much lower mass than an elephant, it would have to have a much higher velocity to achieve the same momentum as an elephant. But it is definitely possible.