Volume of a cylinder formula:
V= h(pi×r^2)
If the diameter is 10in, then the radius is 5in
Substitute given values into the formula:
V=20(3.14×5^2)
V=20(78.5)
V=1570in
        
             
        
        
        
Options for part A are as follows:
A) A mutation in the operator sequence
B) A mutation in the lac-Z gene
C) A mutation in the lac-Y gene
D) A super repressor mutation
Answer:
The correct answer:
Part a - A mutation in the operator sequence
Part b - It ensures that a cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment
Part C. true.
Explanation:
part a: 
If there is a mutation in the operator sequence leads to prevent binding of the repressor which leads to allowing constitutive expression of the genes various conditions.
part b:
The biological role of the lac operon makes sure that the cell dedicates resources to the production of enzymes involved in lactose metabolism only when lactose is available in the environment
Part c:
RNA polymerase cannot transcribe the structural genes due to the repressor binds to the lac operator, therefore, the proper function of the lac operon is possible when the placement of the operator sequence between the promotor and the structural genes.
 
        
             
        
        
        
Earth's mantle plays an important role in the evolution of the crust and provides the thermal and mechanical driving forces for plate tectonics. Heat liberated by the core is transferred into the mantle where most of it (> 90%) is convected through the mantle to the base of the lithosphere.
        
                    
             
        
        
        
The epiglottis is a flap in the back of your tongue that prevents food from entering the larynx. When your mouth is closed, the epiglottis is in place and blocks the larynx opening. If your mouth is open, the flap lifts and the larynx is no longer blocked so you can breathe. This is why it's important to not chew with your mouth open... if you do, then food can go down the larynx by mistake.