FCAT Grade 8 Science Assessment Practice Questions

Explanation
The lung belongs to the respiratory system because it is the primary organ responsible for the exchange of oxygen and carbon dioxide in the body. It helps in the process of respiration by taking in oxygen from the air and releasing carbon dioxide as a waste product. The respiratory system also includes other structures such as the trachea, bronchi, and diaphragm, which work together to facilitate breathing and ensure the proper functioning of the respiratory process.

Explanation
The unit of force is Newton. This is because Newton is the SI unit for measuring force. It is named after Sir Isaac Newton, a renowned physicist who made significant contributions to the study of force and motion. The Newton is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. Therefore, Newton is the correct unit for measuring force.

Explanation
The unit ratio of mass to volume is known as density. Density is a measure of how much mass is contained within a given volume. It is calculated by dividing the mass of an object by its volume. The density of a substance is a characteristic property and can be used to identify the substance. Therefore, density is the correct answer for the unit ratio of mass to volume.

Explanation
The respiratory organ of fish is the gill. Gill is a specialized structure that allows fish to extract oxygen from water. It consists of thin filaments that are rich in blood vessels, which help in the exchange of gases. As water passes over the gills, oxygen is absorbed from the water and carbon dioxide is released. This adaptation allows fish to respire efficiently in their aquatic environment.

Explanation
The primary producer of a biological community is responsible for converting energy from the sun into organic matter through photosynthesis. They are the base of the food chain and provide energy and nutrients for all other organisms in the community. Plants are the primary producers as they are able to produce their own food using sunlight, water, and carbon dioxide. They play a crucial role in maintaining the balance and stability of the ecosystem.

Explanation
The Mediterranean is not considered an ocean because it is a sea, specifically a sea that is connected to the Atlantic Ocean. Oceans are large bodies of saltwater that cover a significant portion of the Earth's surface, whereas seas are smaller bodies of saltwater that are partially enclosed by land. The Indian Ocean, Atlantic Ocean, and Pacific Ocean are all examples of oceans.

Explanation
A bat is a mammal because it possesses all the defining characteristics of mammals. It has fur or hair, gives birth to live young, and nurses its offspring with milk. Bats also have a specialized skeletal structure that allows them to fly, which is a unique characteristic of mammals. On the other hand, scorpions, cockroaches, and snails are not mammals. Scorpions are arachnids, cockroaches are insects, and snails are mollusks. Therefore, the correct answer is bat.

Explanation
A young one of a toad is called a tadpole. Tadpoles are the larval stage of a toad's life cycle, starting as eggs and developing into fully grown toads. They have a long tail and live in water, breathing through gills. As they grow, tadpoles undergo metamorphosis, where they develop legs and lungs, eventually transitioning into adult toads.

Explanation
Jupiter has 79 known satellites, making it the planet with the most moons in our solar system. These moons vary in size and composition, with the four largest ones known as the Galilean moons: Io, Europa, Ganymede, and Callisto. These moons were discovered by Galileo Galilei in 1610 and are among the most fascinating objects in our solar system, with some potentially harboring conditions suitable for life. Therefore, the correct answer is 12.

Explanation
The product of mass and velocity is called momentum. Momentum is a vector quantity that represents the motion of an object and is calculated by multiplying the mass of the object by its velocity. It is a measure of the object's tendency to keep moving in the same direction with the same speed.