Ascientific law:
a. is well tested
b. is usually an equation
c. is an example of a scientific model
d. all of the above

D. All of the above

This is true because scientific laws are all 3:
• They are well tested (to become a definite law)
• They are usually in equation form; for example: (e=mc^2)
• They are usually an example of a scientific model. The model generally will demonstrate the principle.

Hope this helps! ✅