the process of photosynthesis explains how ___ able to use the energy in sunlight to manufacture foods from the simple chemicals in air and water. A. green plants B. green plants are C. planting greens D. with green plants are

For more than a decade, _____ that certain species are becoming scarce. A. the warnings B. warn the bird-watchers C. birdwatchers have warned D. a warning for bird-watchers

Early in the eighteenth century, Halley accurately predicted when _____ of 1682 would return. A. the comet B. was the comet C. the comet was D. had the comet

Minute Man National Historical Park is a monument to where _____ A. the beginning of the Revolutionary War B. in the beginning of the RW C.the Revolutionary War to begin D. the Revolutionary War began

The National Institute of Dental Research estimates ____ in fluoridated areas have about 25 percent less tooth decay than children elsewhere. A. for school children B. school's children C. that school children D. that for school children

Today, the true story of _________ at Little Bighorn remains a mystery. A. happened B. it happened C. what happened D. what happening

We do not ____ the bow drill was first developed for woodworking or fire making. A. whether it B. know whether it C. know whether D. sure whether

Lack of clarity about _____ the party in the coming year will be removed at the party's convention. A. will lead B. lead C. they will lead D. who will lead

No single factor explains why ______ vary so greatly among individuals. A. aging affects B. the effects of aging C. aging has an effect D. the aging effect

Tests on the colors of cars were conducted at the University of California to determine ___ the safest colors for cars. A. which B. which were C. if D. how were