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.
These whales have strong sphincter muscles surrounding their blowhole in order to prevent water from coming in and filling their lungs, which could cause these marine mammals to drown. During deep dives the blue whale can hold its breath for up to 90 minutes before resurfacing for air, however most dives usually last less than 30 minutes.