What is the missing first step of the following process:  -  The top layer are &#x27;doped&#x27; with impurities to allow a negative charge - The bottom layer are &#x27;doped&#x27; to allow for a positive charge - This produces an electric field that allows electrons to flow from negative to positve - Sunlight enters the cell - Energy from sunlight knocks electrons loose in both fields - This prevents the flow of electrons from negative to positive - Adding an external circuit allows the exchange to continue - Give the cells owner a flow of electricity.
Ans: A photovoltaic cell is created with two layers of semiconductor material

What is the missing first step of the following process:  -  The air goes down the esophagus - The air moves into the lungs - The carbon dioxide is removed - The remaining oxygen enters the body - The remaining carbon dioxide is expelled through the mouth.
Ans: Air is drawn in through the mouth

What is the missing first step of the following process:  -  Enters the lungs - The oxygen fills the sacs in your lungs - Carbon dioxide is removed from the lungs and exhaled - The oxygen is pass throughout your body.
Ans: Air is taken through the mouth

What is the missing first step of the following process:  -  The sound waves hit an object - Echoes are produced - The echo returns to the bat&#x27;s ears - The bat hears the echo - The bat can figure out where the object is located.

Ans: The bat sends out sound waves from their mouth or nose