Highlight the one with more Kinetic Energy and briefly explain why.

A 25 kg rock and 35 kg rock rolling down a hill?

A car traveling 25 mph or a bike traveling 10 mph?

An ant running down a sidewalk or a toddler running down a sidewalk?

A full plane or an empty plane (both are flying at the same velocity)?

Write down one real-world example of kinetic energy.

A 25 kg rock and 35 kg rock rolling down a hill?

KE = 1/2*m*v^2
more mass more KE

A car traveling 25 mph or a bike traveling 10 mph?
See above. Higher velocity more KE

An ant running down a sidewalk or a toddler running down a sidewalk?
see above. Compare mass of an ant with mass of a toddler.
A full plane or an empty plane (both are flying at the same velocity)?
See above. A full plane has more mass than an empty plane, assuming both planes have the same mass when empty.