TEST ON FUNDAMENTAL CONCEPTS 641 



(3) causes changes in organisms that may be inheritable; (4) causes 

 changes in organisms that are not inheritable. 



II. Examples of asexual reproduction are (5) conjugation of spir- 

 ogyra; (6) budding of yeast; (7) egg laying of fish; (8) grafting 

 of trees. 



III. Hereditary qualities are believed to be handed down from 

 one generation to another (9) through the protoplasm of the body 

 cells; (10) by means of genes found in the chromosomes; (11) unless 

 the environment changes; (12) through the sex cells only. 



IV. Variations (13) are changes in structure which may occur in all 

 succeeding generations ; (14) are continuous or discontinuous ; (15) if 

 continuous, are valuable to plant or animal breeders, as they form new 

 varieties that breed true; (16) cause various types of animals to be 

 developed. 



V. Hybridizing (17) consists in crossing two related species ; 



(18) always results in the formation of offspring that breed true ; 



(19) results in the formation of plants which differ from their parents ; 



(20) is a method of breeding. 



VI. Genes are (21) believed to contain the determiners of unit 

 characters ; (22) found in all body cells ; (23) found in the chromo- 

 somes ; (24) found in both sperm and egg cells. 



VII. Mendel's laws of heredity (25) show that certain character- 

 istics are inheritable; (26) are not used by breeders as they are not 

 reliable ; (27) show that certain characters are dominant over others ; 

 (28) show that unit characters may be segregated out in the ratio of 

 3 : 1 in the second filial generation. 



VIII. Studies of various families show that (29) feeble-mindedness 

 is inherited; (30) artistic ability is inherited; (31) tuberculosis is 

 inherited; (32) persons possessing good characteristics will usually 

 have children with good characteristics. 



IX. Observation of the laws of heredity make possible (33) the 

 development of plants that have desirable characters ; (34) the 

 improvement of the human race; (35) the gradual elimination of 

 plants or animals that possess undesirable characters; (36) the pro- 

 duction of animals that are entirely different from their parents. 



X. Mutants (37) breed true; (38) do not breed true; (39) vary 

 largely from their ancestors ; (40) are used as starting point for a new 

 species of plants or animals. 



