1. The patella, commonly known as the kneecap, is an example of a:

A. Sesamoid bone
B. Long bone
C. Short bone
D. Irregular bone

Correct answer: A

Rationale: The patella, or kneecap, is a sesamoid bone. Sesamoid bones are small bones that develop within tendons, typically where they pass over joints. The patella functions to protect the knee joint and enhance the leverage of the quadriceps muscle. Its location and function align with those of a sesamoid bone, making option A the correct choice. Long bones, such as the femur, are characterized by their elongated shape and serve as levers for movement. Short bones, like those in the wrist and ankle, provide support and stability. Irregular bones, such as the vertebrae, have complex shapes and functions. Therefore, option A is the most appropriate answer in this context.

2. A substance that can donate a hydroxide ion (OH-) in solution is classified as a:

A. Salt
B. Base
C. Neutral compound
D. Dehydrating agent

Correct answer: B

Rationale: Bases accept protons (H+) and can donate hydroxide ions

3. What is the law that states energy can neither be created nor destroyed?

A. Law of Conservation of Matter
B. Law of Conservation of Energy
C. Law of Universal Gravitation
D. Law of Inertia

Correct answer: B

Rationale: Law of Conservation of Energy. This law applies to both chemical and physical processes, including chemical reactions.

4. In plant cells, what structure provides rigidity and support?

A. Cell membrane
B. Golgi apparatus
C. Plastid
D. Cell wall

Correct answer: D

Rationale: The correct answer is D: Cell wall. The cell wall is a rigid structure found in plant cells that provides support and protection. It is composed of cellulose and other materials, forming a tough outer layer that helps maintain the cell's shape and prevents it from bursting under pressure. The cell membrane (option A) is a semi-permeable barrier that surrounds the cell but does not provide rigidity. The Golgi apparatus (option B) is involved in sorting and packaging proteins. Plastids (option C) are organelles responsible for functions like photosynthesis and storage, but they do not provide rigidity and support like the cell wall does.

5. A water fountain has a spherical base (diameter 50cm) and a cylindrical body (diameter 30cm, height 80cm) on top. What is the total surface area of the fountain (excluding the water surface)?

A. 3142 sq cm
B. 4712 sq cm
C. 5486 sq cm
D. 7957 sq cm

Correct answer: C

Rationale: Calculate the surface area of the sphere and the cylinder separately, then add them up.

6. The kidneys are bean-shaped organs responsible for filtering waste products from the blood. What is the main nitrogenous waste product the kidneys eliminate?

A. Carbon dioxide
B. Ammonia
C. Urea
D. Glucose

Correct answer: C

Rationale: The correct answer is C: Urea. The kidneys filter waste products from the blood to maintain a proper balance of electrolytes and remove toxins. Urea is the main nitrogenous waste product formed from the breakdown of proteins in the liver. It is then excreted by the kidneys through urine. Carbon dioxide is a waste product of cellular respiration and is eliminated primarily through the lungs. Ammonia is a toxic compound that is converted to urea in the liver before being excreted by the kidneys. Glucose is a sugar that is normally reabsorbed by the kidneys and not excreted as waste.