1. Nutrients are absorbed into the bloodstream through which part of the digestive system?

A. Stomach
B. Large intestine
C. Small intestine
D. Esophagus

Correct answer: C

Rationale: The correct answer is C: Small intestine. The small intestine is where most of the absorption of nutrients takes place in the digestive system. Its inner lining is covered with tiny finger-like projections called villi, which increase the surface area for absorption. Nutrients such as carbohydrates, proteins, fats, vitamins, and minerals are absorbed into the bloodstream through the walls of the small intestine. The stomach primarily helps with the initial digestion of food, the large intestine absorbs water and salts, and the esophagus is the tube that carries food from the mouth to the stomach. Therefore, the small intestine is the main site of nutrient absorption in the digestive system.

2. Which statement accurately describes the relationship between electron configuration and the periodic table?

A. Elements within the same period have similar electron configurations.
B. Elements within the same group have similar electron configurations in their outermost shell.
C. Electron configuration has no influence on an element's position on the periodic table.
D. The number of electron shells an element has determines its group on the periodic table.

Correct answer: B

Rationale: Elements within the same group have similar electron configurations in their outermost shell. This explains why elements in the same group often share similar chemical properties.

3. Which of the following best describes a chemical change?

A. Melting ice to form water
B. Dissolving sugar in water
C. Burning wood to produce ash
D. Crushing a can to reduce its size

Correct answer: c

Rationale: Chemical changes involve the formation of new substances with different chemical properties. Burning wood involves a chemical reaction where wood undergoes combustion, breaking down its chemical structure to produce new substances like ash and gases.

4. The number of protons in an atom determines its:

A. Mass number
B. Atomic number
C. Atomic number
D. Valence electron count

Correct answer: B

Rationale: The atomic number (Z) equals the number of protons and defines an element's core identity.

5. Which type of waves exhibit both longitudinal and transverse motion?

A. Electromagnetic waves
B. Surface waves
C. Mechanical waves
D. Sound waves

Correct answer: b

Rationale: Surface waves, like those on water surfaces, exhibit both longitudinal and transverse motion.

6. A ball is thrown upwards. At the peak of its trajectory, which of the following forces is acting on the ball?

A. Gravity only
B. Gravity and air resistance only
C. Neither gravity nor air resistance
D. All of the above

Correct answer: C

Rationale: At the peak of its trajectory, the ball has momentarily stopped moving upwards and has not yet started to fall back down. Therefore, there is no longer a net force acting on the ball at that instant. Gravity is acting downwards, but since the ball is not moving, the force of gravity is balanced by an equal and opposite force, resulting in a net force of zero. Similarly, air resistance only affects the ball when it is in motion, so at the peak where the ball momentarily stops, there is no air resistance force. Therefore, at the peak of its trajectory, neither gravity nor air resistance is acting on the ball, making option C the correct answer.