Answer:
4
Explanation:
<em>The number of progeny expected to display the dominant phenotype for both the A and B genes should be 4.</em>
<u>A test cross usually involves crossing an individual whose zygosity is in doubt with an individual that is recessive for both alleles so as to ascertain the zygosity of the former.</u> Hence, for a test cross involving AaBb:
AaBb x aabb
Progeny:
4 AaBb
4 Aabb
4 aaBb
4 aabb
<em>Therefore, the number of progeny expected to display the dominant phenotype for both the A and B genes is 4.</em>
