Why did Gombrich believe this a little history of the world would be so challenging to write?

The correct answer to this open question is the following.

Although there are no options attached, we can comment on the following.

Ernst Gombrich wrote his book "A Little History of the World" in 1935. In 2001 he committed to writing the book in English for his American and English readers because he wanted to use simple terms so kids could understand the historical events such as the first humans on the planet to World War 1. The problem was that Walter Neurath, his publisher, pressed him to end the book just in six weeks in order to publish it as soon as possible. That is why he thought it was too challenging to write.

islam spread slowly through much of africa through trade and preaching.

this is false

richard nixon was the 37th president of the united state and didn't serve as a vice president for any president before him