Why does more crossing over occur between two distantly linked genes than between two genes that are very close together on the same chromosome?

Which of the following gametes can be formed from the genotype AaBb if AB and ab are linked?

An experiment that was performed found the recombination frequency between two genes was 12.5%. What is the distance (in mapping units) between two genes?

Which of the following terms describes two copies of the same chromosome?

Genes E and H are syntenic in an experimental organism with the genotype EH/eh. Assume that during each meiosis, one crossover occurs between these genes. No homologous chromosomes escape crossover, and none undergo double crossover. Are genes E and H genetically linked? Why or why not? What is the proportion of parental gametes produced by meiosis?