Tech A says that fixed calipers use one or more pistons only on one side of the rotor. Tech B says that sliding/fixed calipers use one or more pistons on both sides of the rotor. Who is correct?

Ithink it’s a but it might be wrong so sorry

Yo idk the answer so here i am

What is this supossed to be?

The earth's inner core is the earth's innermost part. it is primarily a solid ball with a radius of about 1,220 km (760 miles), which is about 70% of the moon's radius.[1][2] it is composed of an iron–nickel alloy and some light elements. the temperature at the inner core's surface is approximately 5,700 k (5,430 °c), which is about the temperature at the surface of the sun.