Consider the following list of commonly found items and their pH values:

• Baking Soda (8.3)
• Battery Acid (1.0)
• Beer (4.2)
• Bleach (12.8)
• Butter (6.1-6.4)
• Coffee (5.0).
• Egg Whites (7.6-8.0)
• Grapes (3.5-4.5)
• Milk Magnesia (10.6)
• Tomato (4.0-4.5)
• Vinegar (2.2)
• White Bread (5.0-6.0)

Which list includes only acids?

The marked structure is the dendrite, a branched projection of a neuron that extends from the cell body (soma). Dendrites are specialized for receiving synaptic input from other neurons and transmitting that electrical signal toward the cell body. They increase the surface area available for synaptic connections, allowing integration of multiple incoming signals. Functionally, dendrites play a key role in determining whether a neuron reaches the threshold for action potential generation at the axon hillock.

A. Axon terminal: The axon terminal is the distal end of the axon where neurotransmitters are released into the synaptic cleft. It forms synapses with other neurons, muscles, or glands to transmit signals to the next cell. Unlike dendrites, which receive input, axon terminals are involved in signal output. They are usually found at the far end of long axonal projections rather than branching near the cell body.

B. Axon: The axon is a long, single projection that carries electrical impulses away from the neuron’s cell body toward target cells. It is often myelinated to increase conduction speed and ends in terminal branches. Unlike dendrites, it is typically singular, longer, and specialized for signal transmission rather than reception.

C. Dendrite: Dendrites are multiple, short, highly branched extensions of the neuron that receive incoming synaptic signals. They conduct graded potentials toward the soma, where integration occurs to determine neuronal firing. Their extensive branching increases receptive surface area, making them essential for neural communication. Their structure and function as primary input receivers make them the correct answer.

D. Cell body: The cell body (soma) contains the nucleus and most organelles required for neuronal metabolism and protein synthesis. It integrates incoming signals from dendrites and maintains cell function. Unlike dendrites, it is not a branching structure but a central region of the neuron. It serves as the metabolic center rather than the primary input surface.

The marked structure is the mandible, which is the largest and strongest facial bone forming the lower jaw. It is the only movable bone of the skull, articulating with the temporal bone at the temporomandibular joint (TMJ). The mandible supports the lower teeth and plays a critical role in mastication, speech, and facial structure. It is shaped like a horseshoe and consists of the body and two rami.

A. Maxilla: The maxilla forms the upper jaw and is a fixed bone of the facial skeleton. It contributes to the hard palate, the floor of the orbit, and the upper dental arch. Unlike the mandible, it is immovable and does not form a joint for chewing motion.

B. Zygomatic bone: The zygomatic bone forms the prominence of the cheek and part of the lateral wall of the orbit. It contributes to facial contour and protection of the eye. Compared to the mandible, it is a non-movable facial bone and does not participate in jaw movement or mastication.

C. Mandible: The mandible is the lower jawbone and the only movable bone of the skull. It articulates with the temporal bone at the TMJ, allowing chewing, speaking, and mouth opening. It supports the lower teeth and provides attachment for muscles of mastication such as the masseter and temporalis. Since the marked structure is the movable lower jaw, it corresponds to the mandible.

D. Temporal bone: The temporal bone forms part of the lateral skull and houses structures of the ear. It contributes to the cranial base and forms the socket for the mandibular articulation (TMJ). However, it is not the jawbone itself but rather the bone that articulates with the mandible.