Thomas Hunt Morgan was awarded the Nobel Prize for his work on:

The theory of recombination of linked genes due to crossing over of chromosomes during the pachytene stage of meiosis was put forward by:

$A$ scientist performed a gene mapping experiment in maize. He mapped genes on chromosomes based on the percentage of crossing over between different genes. One map unit corresponds to $1\%$ crossing over or recombination frequency. Based on the study of crossing over in maize, the scientist observed the following recombination percentages between genes $A, B, C,$ and $D$: $A$ and $D = 10\%$, $A$ and $C = 3\%$, $C$ and $D = 7\%$, $A$ and $B = 5\%$, and $C$ and $B = 8\%$. Based on these observations, determine the correct order of genes $A, B, C,$ and $D$ on the chromosome.

Mendel was successful in discovering the principles of inheritance because:

Linkage was first suggested by

Continuous variations are attributed to