Forest rangers sometimes intentionally start an avalanche with explosives. They have a reason. If an avalanche of ice or snow is about to occur, rangers say a (1) _____________ one is better than one without any (2) ______________.

The world's largest flower can be found on the jungle floor of the South Pacific Indonesian islands. One big blossom of this species (3) _______________ 42 inches across. This beautiful reddish flower, which grows on the roots of other plants, (4) ______________ like rotten fish.

The world's largest flower can be found on the jungle floor of the South Pacific Indonesian islands. One big blossom of this species (3) _______________ 42 inches across. This beautiful reddish flower, which grows on the roots of other plants, (4) ______________ like rotten fish.

Your nervous system carries messages at

(5) ___________ speed. If you burn your finger the measure is (6) __________ to the brain, where it is acknowledged and interpreted. Then another message is sent to your finger to pull it away. Total time elapsed: 1/25 of a second.

Your nervous system carries messages at

(5) ___________ speed. If you burn your finger the measure is (6) __________ to the brain, where it is acknowledged and interpreted. Then another message is sent to your finger to pull it away. Total time elapsed: 1/25 of a second.

The (7) ___________ on a golf ball are not mere beauty marks. If the ball had a (8) ____________ surface, a suction pocket would form below it and halt the flight after a hundred yards or so. The dimples break up the suction pocket and enable the ball to stay airborne for up to 250 or 300 yards.

The (7) ___________ on a golf ball are not mere beauty marks. If the ball had a (8) ____________ surface, a suction pocket would form below it and halt the flight after a hundred yards or so. The dimples break up the suction pocket and enable the ball to stay airborne for up to 250 or 300 yards.

Dead skin piles up when there are unusual stresses or friction on the feet. This sometimes causes corns or calluses to (9) __________. The best (10) _________ is to try to correct the problem by buying better-fitting shoes, getting foot supports, or even going barefoot.

Dead skin piles up when there are unusual stresses or friction on the feet. This sometimes causes corns or calluses to (9) __________. The best (10) _________ is to try to correct the problem by buying better-fitting shoes, getting foot supports, or even going barefoot.

The sun is burning itself out. Two hundred million tons of it are destroyed every minute. In spite of this fact, there is no need for alarm.

Fifty billion years will pass before the (11) ________ of the sun becomes a

(12) _______.

The sun is burning itself out. Two hundred million tons of it are destroyed every minute. In spite of this fact, there is no need for alarm.

Fifty billion years will pass before

the (11) ________ of the sun becomes a

(12) _______.