Problem: John Charles Fremont or Fremont (January 21, 1813 - July 13, 1890) was an American explorer, politician, and soldier who, in 1856, became the first candidate of the Republican Party for the office of President of the United States. During the 1840s, when he led five expeditions into the American West, that era's penny press and admiring historians accorded Fremont the sobriquet The Pathfinder. During the Mexican-American War, Fremont, a major in the U.S. Army, took control of California from the California Republic in 1846.

In the fall of 1853, Fremont embarked on another expedition to identify a viable route for a transcontinental railroad along the 38th parallel. The party journeyed between Missouri and San Francisco, California, over a combination of known trails and unexplored terrain. A primary objective was to pass through the Rocky Mountains and Sierra Nevada Mountains during winter to document the amount of snow and the feasibility of winter rail passage along the route. His photographer (daguerreotypist) was Solomon Nunes Carvalho.  Fremont followed the Santa Fe Trail, passing Bent's Fort before heading west and entering the San Luis Valley of Colorado in December. The party then followed the North Branch of the Old Spanish Trail, crossing the Continental Divide at Cochetopa Pass and continuing west into central Utah. But following the trail was made difficult by snow cover. On occasion, they were able to detect evidence of Captain John Gunnison's expedition, which had followed the North Branch just months before.  Weeks of snow and bitter cold took its toll and slowed progress. Nonessential equipment was abandoned and one man died before the struggling party reached the Mormon settlement of Parowan in southwestern Utah on February 8, 1854. After spending two weeks in Parowan to regain strength, the party continued across the Great Basin and entered the Owens Valley near present-day Big Pine, California. Fremont then journeyed south and crossed the Sierra Nevada Mountains and entered the Kern River drainage, which was followed west to the San Joaquin Valley.  Fremont arrived in San Francisco on April 16, 1854. Having completed a winter passage across the mountainous west, Fremont was optimistic that a railroad along the 38th Parallel was viable and that winter travel along the line would be possible through the Rocky Mountains.

Does it say what he did in San Francisco?

Answer with quotes: Fremont arrived in San Francisco on April 16, 1854.

Question:
Sir David Frederick Attenborough  (UK: ; born 8 May 1926) is an English broadcaster and naturalist. He is best known for writing and presenting, in conjunction with the BBC Natural History Unit, the nine natural history documentary series that form the Life collection, which form a comprehensive survey of animal and plant life on Earth. He is a former senior manager at the BBC, having served as controller of BBC Two and director of programming for BBC Television in the 1960s and 1970s. He is the only person to have won BAFTAs for programmes in each of black and white, colour, HD, 3D and 4K.
After leaving the Navy, Attenborough took a position editing children's science textbooks for a publishing company. He soon became disillusioned with the work and in 1950 applied for a job as a radio talk producer with the BBC. Although he was rejected for this job, his CV later attracted the interest of Mary Adams, head of the Talks (factual broadcasting) department of the BBC's fledgling television service.  Attenborough, like most Britons at that time, did not own a television, and he had seen only one programme in his life. However, he accepted Adams' offer of a three-month training course, and in 1952 he joined the BBC full-time. Initially discouraged from appearing on camera because Adams thought his teeth were too big, he became a producer for the Talks department, which handled all non-fiction broadcasts. His early projects included the quiz show Animal, Vegetable, Mineral? and Song Hunter, a series about folk music presented by Alan Lomax.  Attenborough's association with natural history programmes began when he produced and presented the three-part series Animal Patterns. The studio-bound programme featured animals from London Zoo, with the naturalist Julian Huxley discussing their use of camouflage, aposematism and courtship displays. Through this programme, Attenborough met Jack Lester, the curator of the zoo's reptile house, and they decided to make a series about an animal-collecting expedition. The result was Zoo Quest, first broadcast in 1954, where Attenborough became the presenter at short notice due to Lester being taken ill.  In 1957, the BBC Natural History Unit was formally established in Bristol. Attenborough was asked to join it, but declined, not wishing to move from London where he and his young family were settled. Instead, he formed his own department, the Travel and Exploration Unit, which allowed him to continue to front Zoo Quest as well as produce other documentaries, notably the Travellers' Tales and Adventure series.  In the early 1960s, Attenborough resigned from the permanent staff of the BBC to study for a postgraduate degree in social anthropology at the London School of Economics, interweaving his study with further filming. However, he accepted an invitation to return to the BBC as controller of BBC Two before he could finish the degree.
Answer this question using a quote from the text above:

What kind of work did he first do at BBC?

Answer:
he became a producer for the Talks department,