Answer:
The cross that guarantees a height trait ratio in the offspring of 1 : 1 high/low is Hh X hh (option C).
Explanation:
For a characteristic such as size, where tall (H) is the dominant trait and short (h) is the recessive, the crossing of a tall heterozygous (Hh) individual with a short one will have a probability that half of the offspring will be tall and the other half short.
This can be demonstrated with a Punnett square:
Cross Hh X hh
Alleles H h
h Hh hh
h Hh hh
Based on this result, half of the offspring will be tall, with genotype Hh, and the other half short, with genotype hh, which corresponds to a tall : short ratio of 1 : 1.
In the other options is not possible to obtain this result:
<em>A) HH Xhh = 100% Hh.</em>
<em>B) hh X hh = 100% hh.</em>
<em>D) Hh X Hh = 50% Hh, 25% HH and 25% hh.</em>