does everyone do their homework late sunday night?

Some connecting rods have to lubricate the cylinder wall or piston pin. the answer is letter d. graphite coating can be a major  additive to many  coating  systems and things such as connecting rods.  it functions as a refractory, lubricant, thermal conductor, and electrical conductor for a machine or thing to enhance its work.

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.