What word is used to describe the normal, or target, value for something?

Why is it important to reduce the number of chromosomes in half when forming gametes for sexual reproduction?

How does deforestation affect the water cycle? a. it increases the amount of runoff b. it increases the amount of percolation c. it increases the amount of transpiration d. it increases the amount of precipitationa it increases the amount of runoff

The galapagos island contain 13 species of finches four of the species are seen here it is believed that all of the species had one common ancestor and overtime