What are the 2 reasons why in the last 200 years we've gone from 1 billion humans to 8 billion humans on planet earth?

The world population increased from 1 billion in 1800 to 7.7 billion today.

The world population growth rate declined from 2.2% per year 50 years ago to 1.05% per year.

While winters are rainy, summers are dry. regions with this climate are usually in the eastern part of the continents. they experience hot, humid summers and colder winters. precipitations have a regular distribution throughout the year, but hurricanes are common.