Climate, more than any other single factor, determines the distribution of life on Earth. Climatic boundaries establish the limits within 1 organisms can survive. Plants, 2 more than animals, must be well 3 in order to survive. They cannot move about or 4 shelter but must be equipped to endure whatever weather conditions are 5 to occur. In the harsh 6 of the tundra, for example, low growing mosses, lichens, and a few flowering plants all hug the ground for shelter 7 icy winds.
Animals, 8 their ability to move about and find shelter, are just as much influenced by climate as plants are. Creatures such as camel and the penguin are so 9 specialized that they have an extremely limited distribution. Others, such as bears, are 10 enough to adapt to a range of climates. Ocean dwelling organisms are just as sensitive to climatic changes—in this case temperature and salinity—as land animals. Reef corals can 11 only in clear warm seawater. Certain foraminifers are so sensitive to 12 in their environment that their presence is taken 13 an index of sea temperature. Human beings are 14 the least specialized of all animals and can live almost 15 . Their clothes and their homes act as a sort of "miniature climate" that can be taken with them everywhere.