All public swimming pools should have a lifeguard on duty because not everyone can swim or someone may have an accident. The life guard who can swim should be on watch to keep those accidents from happening and prevent people drowning.
The correct option is C. They had trained and rehearsed for the mission. Originally, the black regiment had prepared for the offensive and was going to lead the charge against the Confederate Army, however one day before the battle they were ordered not to do that and were replaced by white troops. This result in a defeat of the Union Army.
When the Framers created a bicameral legislature, they created a system of checks and balances within Congress by requiring a bill to be passed in both chambers.
The structures, powers, and functions of the House of Representatives and the Senate are different, and these differences can affect the policymaking process: for example, by accelerating it or slowing it down, and by the extent to which bipartisan collaboration is or is not facilitated.