For the use scientific notation (I. e.5e4) no spaces and correct significant digits 125840= 1.2584x10^5
Would the answer be 1e^5??

Hope the image of the frequency formula

It is a product

Adialysis unit requires 78.5 l of water.the estimated digit is 5. 

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.