Explain what is

Fixed Cost?
Variable Cost?
Semi-Variable Costs?​

Fixed Cost-

A fixed cost is a cost that does not change with an increase or decrease in the amount of goods or services produced or sold

Variable cost -

A variable cost is an expense that rises or falls in direct proportion to production volume.

Semi-Variable Costs -

costs that are a combination of the above, with both a fixed and variable elemen

a) walter looks unhealthy

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).