When linked characters or genes are inherited together through two or more generations, it is called

Lesch Nyhan disease is an $X-$linked recessive disorder that causes neurological damage in human beings. $A$ survey of $500$ mates from a caucasion population revealed that $20$ were effected with this disorder. What is the frequency of the normal allele in this population?

In pea plants, red flowers $(R)$ are dominant over to white flowers $(r)$ and tall plants $(T)$ are dominant over to dwarf plants $(t)$. The table below shows the gametes and the possible offsprings produced in a dihybrid cross. The numbers $1$ to $16$ represent the genotypes of each individual cross $(e.g. 3 = RrTT)$

                $RT$      $Rt$     $rT$      $rt$

$RT$             $1$        $2$       $3$       $4$

$Rt$              $5$        $6$       $7$       $8$

$rT$              $9$        $10$     $11$     $12$

$rt$               $13$       $14$     $15$    $16$

If plant $7$ is crossed with plant $12$, then what proportion of the offsprings produced will be homozygous for both the recessive characters

What is the other name for "incomplete dominance''

Example of environmental determination of sex is/are