Answer:
In economics a demand is defined as the quantity of goods and services that customers are capable to buy and that they find desirable to buy at a particular price for that period of time .
Demand is dependent on the customer's needs and wants each customer may have different things that they consider to be needs to them and those they consider as just wants.
This also depends on affordability, if one doesn't have the money to buy the product then the demand isn't effective.
When the price of the product rises usually it's demand decreases and vice versa when the price fall the quantity of that product demanded will increase.
Barter system- A method of exchange when no money is involved.
B and C can't be the answers because they are not exchanging anything.
D can't be the answer either because there is money involved.
So your answer is A) You trade an apple for a banana at school. because you are exchanging something with someone for something else thats not money.
Hope this Helps!!
<span>His fear of dog is a(n) "conditioned response."
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In classical conditioning, the conditioned response it refers to to the already neutral stimulus. For instance, how about we assume that the scent of sustenance is an unconditioned boost, a sentiment hunger in light of the scent is an unconditioned reaction, and the sound of a whistle when you notice the nourishment is the adapted jolt. The molded reaction would feel hungry when you heard the sound of the shriek.
First, do not panic
Next Cut off power in the affected area
Next Call emergency services or an electrician