My jeans were hanging on the clothesline, and a wren tried to build a nest in them.

How should this sentence be changed

This sentence contains no capitalization or punctuation errors, and its grammar, syntax, and spelling are correct as well !!

Explanation:

onto a large boat, and mark the water level that the boat sinks to. then, take the elephant out and put a bunch of marked weights onto the boat until it reaches the same water level. add up the masses of the weights to get the weight of the elephant.

im not sure about this one