Felis domesticus & Felis silvestris. They both belong to the same genus (cats).
Answer:
An object can convert it's potential energy into kinetic energy. For example see the below figure, where potential energy of water has been converted into kinetic energy. A moving body can transfer some of its energy to set another body into motion. ... So, object what you are speaking about is nothing but energy (mass).
Explanation:
There is no such thing as bird years, so your budgie is still 4 years old :)
