Define the term population Density.

Here are the answers to the questions:

1.2.7 Unregistered and informal entry into a country.
A Refugee immigration
B Asylum seeking
C illegal immigration
D Alien migration
Answer: C

1.3.1 Define the term population Density.

Population density is a measurement of population per unit area. It indicates how many people live in a given area, typically expressed as the number of people per square kilometer or square mile.

Here are the final answers:

• 1.2.7: $\boxed{\text{C}}$
• 1.3.1: Population density is the number of people living per unit of area, usually expressed as people per square kilometer.