1. How many phenotypic classes may be generated from athree-point testcross?
A. (3)=27
B. (2)=4
C. (2)3=8
D. (3)2=9
E. It cannot be predicted.

2.__________ bacterial strainsrequire nutritional supplements in order to grow in a minimalmedium.
A. Heterotropic
B. Prototrophic
C. Phototropic
D. Autotrophic
E. Auxotrophic

3. An arg-strain of E. coli istransformed with a plasmid carrying the wild-type (arg+) gene. Thetransformed cells are replica-plated to two minimal medium plates,one supplemented w arginine and one without. The transformed cellswould grow on
A. only the plate supplemented with arginine.
B. only the plate lacking arginine.
C. both plates
D. neither plate
E. the plate supplemented with argine only if a mutationoccured.