I am an artificial indicator. I am liquid in state. I will change my colour in both acidic and basic solution. Who am I

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Individuals who live below the poverty line get seriously ill more often than those who do not what could be the hidden variable in this situation?