K-7 Science Grade Level Content Expectations

All living organisms are composed of cells because cells are the basic structural and functional units of life. Cells carry out all the necessary processes for an organism to survive and reproduce. They are responsible for carrying genetic information, producing energy, and performing specialized functions in different tissues and organs. Whether it is a single-celled organism or a complex multicellular organism, cells are the building blocks of life. Therefore, it is true that all living organisms are composed of cells.

The explanation for the given correct answer is that the sun is indeed the major source of energy for the warming of the earth. The sun emits electromagnetic radiation, including visible light and heat, which reaches the earth and warms its surface. This solar energy is essential for various processes on earth, such as photosynthesis in plants, weather patterns, and the overall climate. Without the sun's energy, the earth would be a cold and lifeless planet.

Water on Earth can be found in three states: solid (ice), liquid (water), and gas (water vapor). Therefore, the statement that water on Earth can be found in two states is incorrect.

The statement "Motion of an object is relative to a point of reference" is true. This means that the motion of an object can only be described in relation to another object or point. For example, if a car is moving at 60 miles per hour, this speed is only meaningful when compared to a reference point, such as the speed of another car or the speed limit on the road. Without a point of reference, it is impossible to determine the motion of an object. Therefore, the statement is true.

This statement is false because in order for a species to survive, reproduction is necessary. Reproduction allows for the passing on of genetic material and the creation of new individuals. Without reproduction, a species would not be able to continue its existence over time. Therefore, all forms must reproduce to survive.