The type of a product doesn't necessarily remain constant. why?

Which of the following statements is not correct? 1) trade allows for specialization. 2) trade has the potential to benefit all nations. 3) trade allows nations to consume outside of their production possibilities curves. 4) absolute advantage is the driving force of specialization.

Transactions on april 1 of the current year, andrea byrd established a business to manage rental property. she completed the following transactions during april: opened a business bank account with a deposit of $45,000 from personal funds. purchased office supplies on account, $2,000. received cash from fees earned for managing rental property, $8,500. paid rent on office and equipment for the month, $5,000. paid creditors on account, $1,375. billed customers for fees earned for managing rental property, $11,250. paid automobile expenses for month, $840, and miscellaneous expenses, $900. paid office salaries, $3,600. determined that the cost of supplies on hand was $550; therefore, the cost of supplies used was $1,450. withdrew cash for personal use, $2,000. required: 1. indicate the effect of each transaction and the balances after each transaction: for those boxes in which no entry is required, leave the box blank. for those boxes in which you must enter subtractive or negative numbers use a minus sign. (example: -300)

mark, a civil engineer, entered into a contract with david. as per the contract, mark agreed to design and build a house for david for a specified fee. mark provided david with an estimation of the total cost and the contract was mutually agreed upon. however, during construction, when mark increased the price due to a miscalculation on his part, david refused to pay the amount. this scenario is an example of a mistake.