Simplify the following text for a Grade 13 native English-speaking person.
Original: There is no explanation for the particular values that physical constants appear to have throughout our universe , such as Planck 's constant h or the gravitational constant G. Several conservation laws have been identified , such as the conservation of charge , momentum , angular momentum and energy ; in many cases , these conservation laws can be related to symmetries or mathematical identities .
Simplified: There is no explanation for the particular values that physical constants appear to have throughout our Universe , such as Planck 's constant h or the gravitational constant G. Several conservation laws have been identified , such as the conservation of charge , conservation of momentum , conservation of angular momentum and conservation of energy .