How can scientists control the flammability of a substance?

Which fact represents evidence for the big bang theory?

Which statement explains why the bonds between non metals tend to be covalent? the bonds are found to be nondirectional they have large differences in electronegativity they have small differences in electronegativity they have ions that produce an electrostatic pull

Is a pencil falling to the floor anon contact force, a force, or a contact force