A muscle that has a pattern of fascicles running along the long axis of the muscle has which of the following fascicle arrangements?

Correct Answer: C

Rationale: Parallel fascicles run along a muscle's long axis, as in sartorius, maximizing range of motion with fibers aligned end-to-end. Circular fascicles (e.g., orbicularis oris) encircle openings, not axial. Pennate fascicles (e.g., deltoid) angle into a tendon, increasing force, not parallel. 'Rectus' describes straight muscles (e.g., rectus abdominis), often parallel, but parallel is the broader term. This arrangement suits lengthy, strap-like muscles, distinguishing it from circular closure, pennate power, or rectus specificity, key for motion range.

Correct Answer: B

Rationale: The kidney's structure is divided into distinct regions, each with specific roles in filtration and urine production. The outermost layer is a granular region containing glomeruli networks of capillaries where blood filtration begins along with proximal and distal tubules that reabsorb nutrients and water. This area, known as the cortex, contrasts with the medulla, which lies deeper and contains renal pyramids for urine concentration. The nephron, while spanning both regions, is the functional unit, not a layer, and pyramids are medullary structures. The cortex's role in initiating filtration via glomeruli and its superficial position make it the outer layer, distinguishing it from deeper structures involved in later urine processing stages. This anatomical arrangement ensures efficient blood processing and waste excretion, with the cortex's position facilitating its primary filtration function.

Correct Answer: A

Rationale: Neurons communicate across small gaps where signals are transmitted chemically or electrically. These spaces, called synapses, lie between a neuron's axon terminal and another's dendrites or cell body, facilitating neurotransmitter release and signal propagation. Dendrites receive signals but aren't the gap. Interneurons connect neurons, not define spaces. Ganglia are neuron clusters, not gaps. Synapses' role as the critical junction for neural communication, enabling brain function and reflexes, distinguishes them, reflecting their structural and functional significance in the nervous system.

Correct Answer: B

Rationale: Close evolutionary relationships are best shown by genetic similarity. Amino acid sequences in proteins, encoded by DNA, reflect shared ancestry highly conserved sequences indicate recent divergence, as with hemoglobin in mammals. Bone structure suggests relation but converges in unrelated species (e.g., bird and bat wings). Reproduction and respiration methods vary widely even among kin. Protein sequences' molecular precision, tied to genetic heritage, outweighs morphological or functional traits, making it the gold standard in phylogenetic analysis.

Correct Answer: B

Rationale: An equal-armed balance requires equal torque (weight × distance) on both sides. Initially, 20 washers balance 10 bolts, so one bolt equals two washers in weight (20/10 = 2). Adding four bolts increases that side's weight by four bolts, equivalent to 4 × 2 = 8 washers. To maintain balance, eight washers must be added to the other side, keeping total 'washer-equivalents' equal (20 + 8 = 28 vs. 10 × 2 + 4 × 2 = 28). Other options misalign this ratio, making eight the precise counterbalance.