1. Which part of the neuron receives incoming signals from other neurons and conducts them toward the cell body?

A. Axon
B. Dendrite
C. Synapse
D. Myelin sheath

Correct answer: b

Rationale: The correct answer is B: Dendrite. Dendrites are the part of the neuron that receive incoming signals from other neurons and conduct them toward the cell body. They play a crucial role in communication between neurons by receiving neurotransmitters released from neighboring neurons. Axons transmit signals away from the cell body, synapses are the junctions where neurons communicate with each other, and myelin sheath is a fatty insulation that surrounds and protects axons. Therefore, in this scenario, dendrites are specifically responsible for receiving and conducting incoming signals towards the cell body.

2. How many moles of water are produced when 0.5 moles of methane (CH4) react with excess oxygen?

A. 0.5 moles
B. 1 mole
C. 2 moles
D. 3 moles

Correct answer: c

Rationale: The balanced equation is CH4 + 2O2 â†’ CO2 + 2H2O, indicating a 1:2 ratio between CH4 and H2O.

3. What is the general formula for an alkene?

A. CnH2n+2
B. CnH2n
C. CnH2n-2
D. CnH2n+1

Correct answer: B

Rationale: The general formula for an alkene is $C_nH_{2n}$, indicating the presence of a double bond between carbon atoms.

4. What is the absolute value of -7?

A. 49
B. 17
C. 7
D. 14

Correct answer: A

Rationale: Absolute value refers to the non-negative distance of a number from zero. Regardless of being positive or negative, 7 is its distance from zero.

5. The muscular diaphragm plays a vital role in respiration. When it contracts, it:

A. Increases lung volume for inhalation
B. Decreases lung volume for exhalation
C. Filters dust and particles from inhaled air
D. Produces mucus to lubricate the airways

Correct answer: A

Rationale: The diaphragm is a crucial muscle involved in respiration. When the diaphragm contracts, it flattens and moves downwards, increasing the volume in the thoracic cavity. This expansion creates a negative pressure in the lungs, causing air to rush in during inhalation. Therefore, option A, 'Increases lung volume for inhalation,' is the correct answer. The diaphragm's contraction facilitates the breathing process by creating space for the lungs to expand and take in air, making it essential for proper respiration.

6. What is the Aufbau principle?

A. The principle that electrons fill orbitals in order of increasing energy.
B. The principle that electrons cannot be in the same orbital with the same spin.
C. The principle that the maximum number of electrons in an orbital is 2n^2, where n is the energy level of the orbital.
D. The principle that the attractive force between an electron and the nucleus is inversely proportional to the distance between them.

Correct answer: A

Rationale: The Aufbau principle is a fundamental concept in atomic structure that determines the order in which electrons fill the available orbitals in an atom. It states that electrons occupy orbitals in order of increasing energy levels, starting with the lowest energy level and progressing to higher energy levels. This principle is based on the fact that electrons in lower energy levels are more stable and have a lower energy state than electrons in higher energy levels.