Question

Choose the correct statements among the following
A) Genes which code for a pair of contrasting traits are called homozygous.
B) Through artificial selection and domestication from ancestral wild cows, Sahiwal cows in Punjab were identified.
C) An organism of dominant phenotype is crossed with a recessive parent to predict the genotype of test organism.
D) Mendal developed the graphical representation to indicate all possible union of gamets.

• A. A, B
• B. B, C
• C. A, D
• D. C, D

Hint:

A test cross always uses a homozygous recessive parent.
If the offspring ratio is 1:1, the dominant parent was heterozygous. If all offspring show the dominant trait, the parent was homozygous.

Answer 1

The Correct Option is B

Step 1: Check the vocabulary in statement A.
Genes controlling a pair of contrasting traits are called alleles, not homozygous, so A mixes up two different terms and is false.
Step 2: Check the breeding history in statement B.
Sahiwal cattle in Punjab are indeed a product of selective breeding and domestication from ancestral wild cattle, so B is true.
Step 3: Check the test cross logic in statement C.
Crossing a dominant-phenotype individual with a homozygous recessive parent is exactly how a test cross reveals whether the dominant individual is homozygous or heterozygous, so C is true.
Step 4: Check the history in statement D.
The graphical grid for combining gametes is the Punnett square, devised by Reginald Punnett, not Mendel, so D is false.
Final answer: Option 2, B and C.