churn in Business English. churnnoun [ U ] Preventing customer churn is a major concern for mobile service providers, since 20-40% of customers leave their providers in a given year. Employee churn for new hires increased by 33% for the third straight year.
For 18 months, the baby nurses while its mother is on land, or it swims underwater to suckle. When it dives, the calf closes its nose and ears to block out water. All hippos have this ability. They also have membranes that cover and protect their eyes while they are underwater.
gill in Science. The organ that enables most aquatic animals to take dissolved oxygen from the water. It consists of a series of membranes that have many small blood vessels. Oxygen passes into the bloodstream and carbon dioxide passes out of it as water flows across the membranes.