Every object is composed of atoms.Atoms are further composed of sub atomic particles like protons , neutrons ,electrons etc.
The atomic particles too are composed of anti-particles which have same mass as particles like neutrons,protons ,electrons but they have opposite charge.These anti-particles are produced naturally in radioactive decays.
Antiproton is different from electron because antiprotons are antiparticles from protons with same mass but electrons are not.
The branch of physics that deals with study of constituents of a matter is called particle physics.
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