Pollution is harmful material added to the land, the air or the water. A wrapper on the ground is land pollution. Smoke from burning rubbish is air pollution. Oil, sewage or plastic in a river or the sea is water pollution. The same plastic object can become more than one kind if it is burned or washed into a drain.

Standard 3 asks you to judge the effects and to argue for reducing pollution. The photograph shows a beach covered with plastic. It was taken in Accra, Ghana, not in Trinidad. The problem is the same one we see on our own coasts: animals can eat the plastic or become tangled, and people lose a clean place to fish and swim.

Land pollution includes litter, dumps, and waste left in a yard or a forest. It can cut animals, block drains and make soil unfit for a garden.

Air pollution includes smoke from burning rubbish, exhaust from many vehicles, and dust from a bare construction site. You see it and sometimes you smell it. It can make breathing harder.

Water pollution includes sewage, oil, soap suds poured into a river, farm chemicals, and plastic that washes out to sea. It harms fish, crabs and birds, and it can make water unsafe to drink or swim in.

On land, animals can swallow wrappers or cut their feet. Plants may not grow in soil full of oil or rubbish. Drains blocked by litter flood a road when rain comes.

In the air, smoke irritates eyes and lungs. Children with asthma can suffer more on a smoky day. Soot settles on leaves and houses.

In the water, fish and crabs can die in oily or soapy water. A bird can tangle in fishing line. A turtle or a fish can mistake plastic for food. People who eat those animals, or who drink dirty water, can be harmed too. Pollution moves through the food webs you have just studied.

Simple strategies: put litter in a bin, reuse a bottle, do not burn plastic, pour oil and paint at a proper collection point and never down a drain, and join a clean-up with an adult and gloves. Tell an adult about a spill you did not cause. Do not pick up broken glass, needles or unknown chemicals yourself.

Why reduce pollution? Living things share the land, the air and the water. We cannot stand outside that sharing. A wetland, a reef and a yard all fail if the water or the air is poisoned. Reducing pollution protects health, food and the places named in the habitat lesson.

An argument needs a reason, not only a slogan. “Do not burn plastic, because the smoke is air pollution and the leftovers can wash into the sea” is stronger than “littering is bad”.