user: What is the largest city in North America?  What is the smallest city in North America?  What is the distance from California to London?  What is the width of the Earth?  What is the distance from the Earth to Mars?  What was the last planet we have discovered?  How far away is the last planet we discovered?

assistant: Do you mean city size in terms of land area or population for your first question.

8558.491 km or 5318 mi is the distance between London and California.

The earth's diameter as it is known for a sphere is 7917 miles or 12741.18 kilometers.

The distance between earth and the moon is 122.27 million miles.

We are constantly discovering new planets so I am unable to answer the sixth and seventh question.

user: I meant in terms of land area for my first question.

Can you try to answer the sixth and seventh question to the best of your abilities as well as the fifth question you have forgotten to answer previously.

assistant: My apologies for forgetting to answer some of your questions.

Here are the answers to your unanswered questions to the best of my abilities.

 1. The largest incorporated municipality in North America is the regional municpality of Woodbuffalo (Alberta, Canada) with a land area of 24570.53 square miles (63,637.38 square kilometers). Some may dispute whether this counts as a city in the strict sense, as the lines between any municipality and a densely populated urban city is somewhat subjective.

 2. The smallest incorporated municipality in North America is Lost Springs (Wyoming, United States) which according to the 2020 census has a total land area of just 0.09 square miles (0.23 square kilometers), and a population of only 4 people.

3. Answered 

4. Answered

 5. The distance between earth and mars varies greatly as the two planets orbit the sun. It can range from approximately 35 million miles to 250 million miles. On average, the distance between them is approximately 140 million miles. 

 6. The last planet discovered in our solar system is Neptune, which was first observed and identified by the French astronomer Urbain Le Verrier on September 23, 1846. However, since then, no new planets have been discovered in our solar system. In recent years, there have been some debates about the status of Pluto, which was once classified as the ninth planet, but is now considered a "dwarf planet" by many astronomers. There have also been searches for hypothetical planets beyond Neptune, which have not yet been confirmed. However, no new planet discoveries have been confirmed in our solar system since the discovery of Neptune.

 7. Neptune is the eighth planet in our solar system, and its distance from the Sun varies depending on its position in its orbit. The average distance between Neptune and the Sun is about 2.8 billion miles (4.5 billion kilometers), or 30 astronomical units (AU). However, because both Neptune and Earth are constantly moving in their orbits, the actual distance between the two planets can vary considerably over time. At its closest approach to Earth, Neptune can be as close as about 2.7 billion miles (4.3 billion kilometers), while at its furthest distance it can be as far as about 2.9 billion miles (4.7 billion kilometers).