Page 18 in which it develops and by the depth, temperature, and the salt content of the water in which the oyster lives. 65. Although mockingbirds superbly mimic the songs and calls of many birds, they can nonetheless be quickly identified as mockingbirds by certain aural clues. 66. Not only can walking fish live out of water, but they can also travel short distances over land. 67. Scientists do not know why dinosaurs became extinct, but some theories postulate that changers in geography, climate, and sea levels were responsible. 68. The science of horticulture, in which the primary concerns are maximum yield and superior quality, utilizes information derived from other sciences. 69. Snow aids farmers by keeping heart in the lower ground levels, thereby saving the seeds from freezing. 70. Even though the precise qualities of hero in literary words may vary over time, the basic exemplary function of the hero seems to remain constant. 71. People in prehistoric times created paints by grinding materials such as plants and clay into power and then adding water. 72. Often very annoying weeds, goldenrods crowd out less hardy plants and act as hosts to many insect pests. 73. Starting around 7000 B.C., and for the next four thousand years, much of the Northern Hemisphere experienced temperatures warmer than at present. 74. When Henry Ford first sought financial backing for making cars, the very notion of farmers and clerks owning automobiles Page 18 |