Final answer:
The probability of an offspring being heterozygous from two heterozygous parents is 50%. In a tetrahybrid cross, the chance of an offspring having a dominant phenotype at all loci is 81/256, using the product rule.
Step-by-step explanation:
The question revolves around predicting offspring genotypes in genetics, which falls within the domain of Biology. Specifically, the probability that an offspring will have a heterozygous genotype from two heterozygous parents is 50%. This is derived from a classic Mendelian genetics scenario where each parent has a genotype of Bb. The Punnett square method or the forked-line method can help us visualize the genetic outcomes that result in the genotype ratios in the offspring.
With regard to the dominant phenotype showing at all four loci in a tetrahybrid cross, the probability would be (3/4) × (3/4) × (3/4) × (3/4), or 81/256, using the product rule of probability because each gene's alleles have a 3/4 chance of being expressed as dominant. It's important to note the distinction between the probability of genotypes versus phenotypes when assessing offspring ratios in genetics.