Physics is explicitly involved in studying which of these activities?
a. the mixing of metals to form an alloy
b. the metabolic functions of a living organism
c. the motion of a spacecraft under gravitational influence
d. the depletion of the atmospheric ozone layer due to pollutants
e. the killing of cancerous cells by radiation therapy

second mirror gathers light from a faraway object and reflects it to another mirror. - a.

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.