How did robert boyles define an atom ?

He measured relationships between volume and pressure of gasses. From his expiraments he concluded that gasses are made up of tiny particles that group together to make different substances.

Boyle's definition of an element was based on the observation that many substances can be decomposed into simpler substances. ... They are therefore the elementary, or simplest, chemical substances. Thus, as Boyle pointed out, an element is any substance that cannot be decomposed into a simpler substance.

a is correct

hope this let me know if it is right

this act gave the federal government the power to relocate any native in the east to territory west of the mississippi river.