Energy.
they are conserved in a safe place
Mass is conserved Total energy is conserved, although it may change form as things mix since most mixtures will have an enthalpy of mixing.
it is white
Yes, this is a simple physical change and matter is always conserved in these. In fact, matter is always conserved except in nuclear reactions where the sum of matter and energy is conserved.
Nah, brah. Momentum and kinetic energy are conserved, but velocity is not. Correct me if I am wrong but from how I interpret this, any collision cause the colliding bodies to change their direction. Thus velocity, which is a vector quantitiy containing direction, is by definition changed in an elastic collision. I guess speed, which is the magnitude of the velocity, can be considered as being conserved?
There is no such thing. Either a thing changes, or it doesn't change. If it doesn't change, it is said to be conserved.
Total charge is always conserved. If an electron is emitted, the remaining particle's charge will change by +1. If a positron is emitted, the remaining particle's charge will change by -1.
Conserved. Energy cannot be created or destroyed, it can only change forms.
Momentum is not conserved when external forces act on a system, such as friction or air resistance, causing a change in the total momentum of the system.
Mass is conserved. This means it remains constant.
No, the mass is conserved.
neither physical or changes its property