Which president oversaw the building of the panama canal, emphasized conservation, and established some of the first national parks?

The answer is Theodore Roosevelt. The 26th President of the United States from 1901 to 1909, Roosevelt was also a naturalist, author, explorer, and soldier among others. He born in October 27, 1858 in New York City and died in January 6, 1919 in Oyster Bay. Among his many feats, the construction of the Panama Canal and the establishment of the first National Parks are the most well-known ones. 

the tallest building in the western hemisphere and the sixth tallest building in the world

offline recommendation systems option b

because recommendation systems produce a list of two ways

1. through collaborative filtering

or

2. through content-based filtering