Scientists, who are now aware of how nautiluses regulate their buoyancy, have been able to dispel erroneous ideas about these creatures.

单项选择题George Washington Carver was esteemed for his contributions in the fields of botany and chemistry.

单项选择题Pendulums are used to regulate motion in some scientific equipments.

单项选择题Manufacturers spend millions of dollars on advertising to entice people to buy their products.

单项选择题The painter Les Quinones, whose graffiti art has been exhibited in New York galleries, has also painted outdoor murals in various Manhattan neighborhoods.

单项选择题The North American desert, a vast belt of inhospitable terrain, stretches erratically down the western side of the continent.