NTN Science

Question 1

What is the basic unit of life?

Accepted Answer

Cell

Answer

The cell is the smallest structural and functional unit of all living organisms.

Question 2

Which of the following is a function of the human skeletal system?

Accepted Answer

Providing structure and protecting internal organs

Answer

The skeletal system provides structural support, enables movement, and protects vital organs.

Question 3

Which element is essential for human red blood cells to carry oxygen?

Accepted Answer

Iron

Answer

Iron is a key component of hemoglobin, the protein in red blood cells that binds and transports oxygen.

Question 4

What process do plants use to convert sunlight into food?

Accepted Answer

Photosynthesis

Answer

Photosynthesis is the process by which plants use sunlight, water, and CO₂ to produce glucose and oxygen.

Question 5

Which of the following correctly describes the difference between a physical change and a chemical change?

Accepted Answer

A chemical change creates a new substance; a physical change does not

Answer

A chemical change produces a new substance with different properties, while a physical change alters only form or appearance.

NTN - National Testing Network Practice Test