10 INTRODUCTION 



animals. All matter such as wood, sugar, and meat, 

 which is made in living things, is called organic matter. 

 All matter like stones and water, which is made outside 

 of living things, is called inorganic. 



Environment. — Plants and animals have accustomed 

 themselves to live in different parts of the world. . Their 

 behavior and habits under these varying conditions form 

 a most interesting part of the study of biology. The sur- 

 roundings of plants and animals, that is, the different con- 

 ditions, the air, water, climate, and soil in which they live, 

 are called their environment. 



