Theoretically, in vitro fertilisation could be performed by collecting the contents from a woman's fallopian tubes or uterus after natural ovulation, mixing it with sperm, and reinserting the fertilised ova into the uterus.
Upstream operations deal primarily with the exploration stages of the oil and gas industry, with upstream firms taking the first steps to first locate, test and drill for oil and gas. Later, once reserves are proven, upstream firms will extract any oil and gas from the reserve.
Upstream and downstream are general business terms referring to an oil or gas company's location in the supply chain. The closer to the end user a function or firm is, the further downstream it is said to be. Raw material extraction or production are elements of the supply chain considered to be upstream. The upstream companies identify oil and natural gas deposits and engage in the extraction of these resources from underground. These firms are often called exploration and production companies. Refiners represent the downstream element of the oil and gas supply chain. Upstream oil and gas operations identify deposits, drill wells, and recover raw materials from underground.