refers to the change in total revenue that results from producing and marketing one additional unit of the product
Dolly is the name of a sheep that has the honor of being the first mammal to be cloned by a group of scientists in England. Dolly was born July 5th, 1997 and she passed away in 2003. She lived for 6 and a half years, as a normal, active ewe.
The most common (and the most accurate) name for a baby sheep is lamb, but the lamb term can accurately be used to describe any sheep which is under a year old. The word lamb is also used to describe the meat of any sheep under a year of age, which is why it can get a bit confusing for folks who are new to sheep.