The correct answer would be - the ratio of phenotypes in an organism cross will tell if the genes are linked or not.
Explanation:
In this question, we perform a test cross with a fruit fly that is heterozygous If we perform a test cross between two parents with identical heterozygous genomes AaBb.
If there is no recombination found in the offspring of this cross it means there are no linkage of genes present. And if there are new or recombinant phenotypes present it means that there are genes linked together.
Organisms that can only grow in a media having specific nutrients included in it are called a fastidious organism, this implies that these organisms have specific nutrient requirements for their growth.
MM 1 represents the minimal media which has basic nutrients present in it, however as the fastidious organisms require some particular or complex nutrients for their growth they can not grow on the minimal media.
Therefore, since the organisms that are given in the question is able to grow on the minimal media MM1, this implies that it is not a fastidious organism.
