Part 1. Definition
Given a text passage, come up with an appropriate title for it. The title should accurately represent what the main focus of the passage is. The title of a passage may be present in the first few sentences of the passage and/or be referred to multiple times in the passage. The title should be 1-5 words long.
Part 2. Example
The Beatles ' rooftop concert was the final public performance of the English rock band the Beatles . On 30 January 1969 , the band , with keyboardist Billy Preston , surprised a central London office and fashion district with an impromptu concert from the roof of the headquarters of the band 's multimedia corporation Apple Corps at 3 Savile Row . In a 42 - minute set , the Beatles were heard playing nine takes of five songs before the Metropolitan Police Service asked them to reduce the volume . Footage from the performance was later used in the 1970 documentary film Let It Be .

Answer: The Beatles' rooftop concert
Explanation: 'The answer given is correct because it is an appropriate title as it is the main subject of the passage.
Part 3. Exercise
In physical cosmology , Big Bang nucleosynthesis ( abbreviated BBN , also known as primordial nucleosynthesis , arch ( a ) eonucleosynthesis , archonucleosynthesis , protonucleosynthesis and pal ( a ) eonucleosynthesis ) refers to the production of nuclei other than those of the lightest isotope of hydrogen ( hydrogen - 1 , H , having a single proton as a nucleus ) during the early phases of the Universe . Primordial nucleosynthesis is believed by most cosmologists to have taken place in the interval from roughly 10 seconds to 20 minutes after the Big Bang , and is calculated to be responsible for the formation of most of the universe 's helium as the isotope helium - 4 ( He ) , along with small amounts of the hydrogen isotope deuterium ( H or D ) , the helium isotope helium - 3 ( He ) , and a very small amount of the lithium isotope lithium - 7 ( Li ) . In addition to these stable nuclei , two unstable or radioactive isotopes were also produced : the heavy hydrogen isotope tritium ( H or T ) ; and the beryllium isotope beryllium - 7 ( Be ) ; but these unstable isotopes later decayed into He and Li , as above .
Answer:
Big Bang nucleosynthesis