Ecology is a field of study that investigates the interrelationships of organisms in the natural world.

This substance undergoes a chemical change when heat is applied.

In this experiment, the substance will undergo a chemical change.

He is majoring in agronomy at university.

He always has a mischievous smile on his face.

He has a warlike personality, always playing strategy games.

He likes toddlers and is always playing with children in the park.

He says that what you like to do, you do well, so he practices drawing every day.

Have a good day at school, son.

When her son goes to school, the mother always says 'see you later'.