1. Muscles that work in opposition to each other, producing opposing movements, are called:

A. Synergists
B. Antagonists
C. Agonists
D. Fixators

Correct answer: B

Rationale: The correct answer is B: 'Antagonists.' Antagonistic muscles are pairs of muscles that work in opposition to each other to produce opposing movements around a joint. For example, the biceps and triceps in the arm act as antagonists - when the biceps contract to bend the elbow, the triceps relax, and vice versa. Synergists (A) are muscles that work together to create a movement, agonists (C) are primary muscles responsible for generating movement, and fixators (D) are muscles that stabilize joints to allow other movements to occur. Understanding the roles of antagonistic muscles is crucial in biomechanics and exercise science.

2. In which part of the cell are proteins modified, sorted, and packaged for transport?

A. Ribosomes
B. Golgi apparatus
C. Endoplasmic reticulum (ER)
D. Lysosomes

Correct answer: B

Rationale: The Golgi apparatus is responsible for modifying, sorting, and packaging proteins for transport. After proteins are synthesized in the rough endoplasmic reticulum (ER), they are transported to the Golgi apparatus where they undergo post-translational modifications and are sorted into vesicles for transport to their final destinations. Ribosomes are responsible for protein synthesis, the endoplasmic reticulum is involved in protein synthesis and folding, and lysosomes are responsible for digesting cellular waste. Therefore, the correct answer is B, Golgi apparatus, as it is specifically involved in the modification, sorting, and packaging of proteins for transport.

3. The energy absorbed during a chemical reaction is called:

A. Kinetic energy
B. Potential energy
C. Heat energy
D. Endothermic energy

Correct answer: D

Rationale: Endothermic means "inward heat," indicating energy is absorbed during the reaction.

4. Which type of wave does not require a medium for propagation?

A. Transverse wave
B. Longitudinal wave
C. Mechanical wave
D. Electromagnetic wave

Correct answer: D

Rationale: Electromagnetic waves, like light and radio waves, can travel through a vacuum, unlike mechanical waves (sound, water waves) that require a medium to vibrate and transmit energy.

5. What property of a substance refers to its ability to undergo a chemical change and form new substances with different properties?

A. Density
B. Mass
C. Reactivity
D. Volume

Correct answer: c

Rationale: Reactivity refers to a substance's ability to undergo a chemical change or reaction, forming new substances with different properties.

6. What is the myelin sheath and what does it do?

A. A group of nerve cells that perform a specific function.
B. A fatty substance that insulates some nerve fibers.
C. A fluid-filled cavity within the brain.
D. The junction between two neurons.

Correct answer: B

Rationale: The correct answer is B. The myelin sheath is a fatty substance that insulates some nerve fibers. It is essential for the proper functioning of the nervous system as it acts as an insulator, allowing for faster transmission of nerve impulses along the axon. Without the myelin sheath, nerve signals could be disrupted or weakened, leading to issues with movement, sensation, and other neurological functions. Options A, C, and D are incorrect as they do not accurately describe the myelin sheath or its function.