Today, two (2.5) children constitute Americans' ideal family size.
Two children is enough to replicate both parents which means that there will always be a steady number of young and old people in a country. Having two children is ideal - anything below that would result in a smaller population.
Answer: a. testing effect
Explanation:
Testing effect is a type of threat to internal validity of an experiment. Internal validity is assessing whether a factor makes a difference in an experiment or not and if it does, whether there is adequate evidence to support this correlation.
Testing as a threat to internal validity is when a second test is taken on the outcome of a first test. Other internal validity threats are history, maturation, instrument modifications.
The working conditions were TERRIBLE ! as factories were being built, businesses were in need of workers ! People worked 14-16 hours each day.
Scarcity refers to the basic economic problem, the gap between limited – that is, scarce – resources and theoretically limitless wants. This situation requires people to make decisions about how to allocate resources efficiently, in order to satisfy basic needs and as many additional wants as possible.
Scarcity dictates that economic decisions must be made regularly in order to manage the availability of resources to meet human needs. Some examples of scarcity include: The gasoline shortage in the 1970's. Coal is used to create energy; the limited amount of this resource that can be mined is an example of scarcity.
Scarcity is simply the concept that human wants (not human needs) exceed the resources available that are necessary to produce the goods used to satisfy those wants. Since economics is the study of how people make choices, without scarcity there would exist no choice and, hence, no economics.
Hope this helps:)
Prob C. cause the sound wave would hit a wall and reflect off of it to come back to your ears.
