Can I ask why the first statement is not possible:)) thanks in advance. Is it because even though it doesn’t survive it should be observed in the phenotype ratio?
The reason why statement 1 is not correct as we know that in a monohybrid cross for a particular trait there are 3 genotypes possible 1 Homozygous dominant(with two dominant allele): 2 heterozygous(one with a dominant and a recessive allele) :1 homozygous recessive(with two recessive allele) phenotypically speaking we have a 3:1 ratio (3 dominant both homozygote and heterozygous) and 1 recessive so we are getting a result as 3:0 which is atypical it’s clear from the ratios that we are having 3 dominant ones but missing the homozygous recessive one (not surviving) due to presence of a lethal gene or any other possibility not much of a concern here.
In a crux we can say that we are left with the dominant ones whereas the recessive ones not being able to survive.
Hope it helps:)
Ohh okay thanks Ujjwal!! The reason I got confused is cause statement 1 says the offspring has BOTH dominant alleles not heterozygous but of course if the dominant allele is diseased then the heterozygous should be too!