6TH GRADE -PRA- FINAL REVIEW

Why does a piece of onion skin not contain any chloroplasts?

Answer explanation

Onion skin is a part of the plant that does not perform photosynthesis, as it is primarily composed of protective layers. Chloroplasts are found in green parts of plants where photosynthesis occurs, not in the non-green onion skin.

Write a definition for the term “bone marrow”

Answer explanation

Bone marrow is a soft, spongy tissue found in the center of bones, responsible for producing blood cells, including red blood cells, white blood cells, and platelets, playing a crucial role in the body's immune system and overall health.

Why would a ball-and-socket joint at the knees create problems for walking?

Answer explanation

A ball-and-socket joint allows for a wide range of motion, which is unsuitable for the knee's primary function of stability and hinge-like movement. This could lead to instability and difficulty in walking.

What happens when we inhale and exhale?

Answer explanation

When we inhale, oxygen enters the lungs and is absorbed into the bloodstream. When we exhale, carbon dioxide is expelled from the lungs. This process is essential for respiration and maintaining oxygen levels in the body.

What does particle theory explain?

Answer explanation

Particle theory explains the behavior and properties of matter by describing how particles interact, move, and are arranged in solids, liquids, and gases, helping to understand states of matter and changes between them.

What is the energy involved in the motion of particles?

Answer explanation

The energy involved in the motion of particles is called kinetic energy. It is the energy that an object possesses due to its motion, which depends on its mass and velocity.

Use the particle model of matter to explain why you can compress a gas easily, but you cannot compress a liquid very easily.

Answer explanation

Gases have widely spaced particles that can move closer together when pressure is applied, making them easy to compress. In contrast, liquids have closely packed particles that are not easily moved, making compression difficult.

Explain what happens to the particles of a gas when it is cooled down.

Answer explanation

When a gas is cooled, its particles lose energy and move slower. This decrease in kinetic energy causes the gas to contract, resulting in reduced pressure and volume as the particles come closer together.

Why can we smell food from far away?

Answer explanation

We can smell food from far away because volatile compounds released by the food travel through the air. Our olfactory receptors detect these molecules, allowing us to perceive the scent even at a distance.

Why doesn’t diffusion happen in solids?

Answer explanation

Diffusion doesn't happen in solids because their particles are tightly packed and vibrate in fixed positions, limiting their ability to move freely and mix, unlike in liquids and gases where particles can move more freely.