They provide better depth perception and peripheral vision.
Answer:
four phenotypes appear in the ratio 9:3:3:1
Explanation:
<em>For a dihybrid cross in which the two genes concerned obey simple dominant/recessive law and are independently assorting, </em><em>four phenotypes are produced in the ratio 9:3:3:1. </em>
The dominant gene takes up the largest ratio (9/16) while the recessive gene takes up the smallest (1/16). Any deviation from 9:3:3:1 and the number of phenotypes produced from a dihybrid cross is an indication that the genes involved do not obey Mendelian laws.
The correct answer is cell wall
A control is a experimental variable that is kept constant or unchanged during an experiment. During a controlled experiment, the controlled variables are held constant to minimize or stabilize their effects on the subject, its unchanging state allows the relationship between the other variables being tested to be better understood.