user: Who is the best NBA player of all time?

assistant: This can be discussed but it is often admitted that Michael Jordan is the best NBA player of all time.

user: What is carnitine?

assistant: Carnitine is a quaternary ammonium compound involved in metabolism in most mammals, plants, and some bacteria. In support of energy metabolism, carnitine transports long-chain fatty acids into mitochondria to be oxidized for free energy production, and also participates in removing products of metabolism from cells. Given its key metabolic roles, carnitine is concentrated in tissues like skeletal and cardiac muscle that metabolize fatty acids as an energy source. Generally individuals, including strict vegetarians, synthesize enough L-carnitine in vivo.

Carnitine exists as one of two stereoisomers (the two enantiomers d-carnitine (S-(+)-) and l-carnitine (R-(−)-)). Both are biologically active, but only l-carnitine naturally occurs in animals, and d-carnitine is toxic as it inhibits the activity of the l-form. At room temperature, pure carnitine is a whiteish powder, and a water-soluble zwitterion with relatively low toxicity. Derived from amino acids, carnitine was first extracted from meat extracts in 1905, leading to its name from Latin, "caro/carnis" or flesh.

Some individuals with genetic or medical disorders (such as preterm infants) cannot make enough carnitine, requiring dietary supplementation. Despite common carnitine supplement consumption among athletes for improved exercise performance or recovery, there is insufficient high-quality clinical evidence to indicate it provides any benefit.

user: Explain the difference of position against the Western Bloc among the Soviet leaders cited in the text.

assistant: Stalin believed that war against the Western Bloc was inevitable.
Krushchev instead believed the two blocs could avoid war because the war was not necessary to establish the Eastern Bloc's superiority; the Western Bloc would fail systemically.
On the other hand, Gorbachev truly believed in peaceful coexistence between the two blocs.