Is there anyone who's good in economics that can me with my questions, ?

One investigating company tracked all credit card purchase during 2012 and measured two variables: (1) the type of credit card used (visa, mastercard, american express, or discover), and (2) the amount (in dollars) of each purchase. identify the level of each variable measured.

James albemarle created a trust fund at the beginning of 2016. the income from this fund will go to his son edward. when edward reaches the age of 25, the principal of the fund will be conveyed to united charities of cleveland. mr. albemarle specified that 75 percent of trustee fees are to be paid from principal. terry jones, cpa, is the trustee. james albemarle transferred cash of $500,000, stocks worth $400,000, and rental property valued at $250,000 to the trustee of this fund. immediately invested cash of $360,000 in bonds issued by the u.s. government. commissions of $7,900 are paid on this transaction. incurred permanent repairs of $9,000 so that the property can be rented. payment is made immediately. received dividends of $8,000. of this amount, $3,000 had been declared prior to the creation of the trust fund. paid insurance expense of $4,000 on the rental property. received rental income of $10,000. paid $8,000 from the trust for trustee services rendered. conveyed cash of $7,000 to edward albemarle.

Google started as one of many internet search engines, amazon started as an online book seller, and ebay began as a site where people could sell used personal items in auctions. these firms have grown to be so large and dominant that they are facing antitrust scrutiny from competition regulators in the us and elsewhere. did these online giants grow by fairly beating competition, or did they use unfair advantages? are there any clouds on the horizon for these firms -- could they face diseconomies of scale or diseconomies of scope as they continue to grow? if so, what factors may limit their continued growth?