Unpleasant though the cockroaches are, biologists say they are essential of the earth’s critical ecosystem.
Root crops are important in developing tropical countries like the Philippines. They are source of food and income to farmers.
Environmentalists are unanimous that organic matter should be kept out of landfill, rivers and oceans. Organic wastes should be segregated from other wastes.
Azolla is a small aquatic fern (usually 1-5 cm large) which grows on saturated or moist soil.