20. Q. What is a species? A. It is the smallest group whose structure is constant.
21. Q. What are individuals? A. They are the units of organic life, forming a complete animated existence.
22. Q. What are peculiarities of races or breeds called? A. Varieties.
23. Q. How are vegetables and animals distinguished from each other? A. By the term kingdom, and the types in each kingdom are called sub-kingdoms.
24. Q. Under what five types or plans of structure can all the multitude of plants which clothe the earth or dwell in the sea be arranged? A. Protophytes, Thallogens, Acrogens, Endogens and Exogens.
25. Q. What are the elementary masses of bioplasm usually called? A. They are usually called cells, even if they are merely pieces of animated jelly, uninclosed by an outside shell or membrane.
26. Q. What is the principal difference between animals and plants? A. The latter can be nourished by simple mineral or chemical (that is unorganized) matter, while animal nutrition requires material which has been organized, or made part of a living being.
27. Q. What do most vegetable cells produce on the outside? A. A membrane or cell wall, within which the living matter is, as it were, imprisoned.
28. Q. What concentrations of living matter are there within a cell? A. A concentration called a nucleus, and sometimes a still further concentration within the nucleus, called nucleolus, or little nucleus.
29. Q. Of what substance is the cell wall composed? A. A substance somewhat like starch, called cellulose.