The Biblical flood would have caused the death of all life on earth, except for those on the arc, which would have resulted in fossils that are now found. Fossils being found in different layers of rocks could have been a result of how they settled as the waters receded.
<u>Answer:</u>
<em>A constant is something whose value cannot be changed and is used for comparison purpose. </em>
<u>Explanation:</u>
The controlled variable is a type of variable whose value is kept constant during the experiment to get the desired or expected result. The difference between constant and a control variable is that the constant can never be changed.
However, the value of control variable can be changed but is kept constant with a purpose in an experiment to get the data. The controlled variable in a battery can be the multi meter that should be used for all the batteries.
These structures are called Vestigial structures, they resemble structures from the organism's ancestors, but don't have a real purpose for them now.
Pray this helps you :)