In pea plants, height is determined by an allele for tallness (T) that is dominant over an allele for shortness (t). What is the
probability that a gamete, selected at random, would carry the short allele (t) in a cross of heterozygous tall pea plants? A. 1/8
B. 1/4
C. 1/2
D. 3/4
Heterozygous organisms show presence of two alternatives alleles for same trait. For plant height, a heterozygous tall plant, will show both the T (for tallness) and t (for shortness) alleles, as T allele is dominant over t allele. When a cross is made between heterozygous tall plants (Tt), there are 50% chances that a randomly selected allele will carry allele for shortness (t) as shown below: Thus, "the probability that a randomly selected gamete will carry 't' allele in a cross between heterozygous tall pea plants, is 1/2."
"Crepuscular" means active at dawn and dusk, so if you wanted to avoid coming across the Gila monster when hiking in Arizona you would want to avoid dawn and dusk.
