According to a study published in Science magazine, brook trout and other varieties of fish exploit turbulent flows swirling around stationary objects in the water to minimize effort and give themselves an energy - saving boost against the current.
फिलहाल संयुक्‍त राष्ट्र एजेंसी अनुमान लगाती है कि 3.8 करोड़ लोगों को एच. आई. वी. है ।