Read the three technical excerpts below regarding specialized military systems. Which statement accurately matches the explicitly stated main idea of each excerpt?
- Excerpt 1: Naval submarines rely on exterior anechoic tiles to minimize acoustic detection by absorbing incoming active sonar pings and dampening internal machinery vibrations. These specialized synthetic rubber or polyurethane tiles are bonded directly to the outer steel hull with marine-grade adhesives. When acoustic pressure waves strike the tile surface, internal air cavities shear and dissipate sound energy into harmless heat. Consequently, submarine acoustic signatures are dramatically reduced, preventing adversary surface vessels and maritime patrol aircraft from acquiring a clear sonar return.Exterior anechoic tiles minimize submarine acoustic detectability by absorbing active sonar signals and dampening hull vibrations.
- Excerpt 2: Field operational units require reliable access to potable water during extended tactical deployments in remote coastal zones. While sediment pre-filters and carbon cartridges remove suspended sand and organic debris, tactical reverse osmosis water purification units rely primarily on high-pressure semipermeable membranes to extract pure potable water from contaminated seawater. High-pressure pumps drive pressurized saline solution against tightly wound spiral polymer sheets, rejecting dissolved salts, heavy metals, and pathogens while permitting fresh water permeation. Regular maintenance involves chemical backflushing to prevent mineral scaling.Tactical reverse osmosis systems extract drinkable water from saline sources through high-pressure semipermeable membranes.
- Excerpt 3: Unlike older gimbaled mechanical gyroscopes that suffer from friction wear and mechanical drift during high-g maneuvers, solid-state navigation systems operate on optical physics. Two counter-propagating laser beams travel along a closed triangular cavity of mirrors, where rotational motion produces a measurable frequency difference known as the Sagnac effect. Optical photodetectors instantly convert this interference frequency into exact heading changes. By eliminating mechanical moving components, ring laser gyroscopes provide resilient, drift-resistant inertial navigation for tactical vehicles.Ring laser gyroscopes provide reliable inertial navigation for tactical platforms by eliminating moving mechanical parts.
Answer
Excerpt 1 matches the statement that exterior anechoic tiles minimize acoustic detectability by absorbing sonar signals and dampening vibrations; Excerpt 2 matches the statement that reverse osmosis systems extract drinkable water through high-pressure semipermeable membranes; Excerpt 3 matches the statement that ring laser gyroscopes provide reliable inertial navigation by eliminating moving mechanical parts.
Each excerpt contains a clearly identifiable explicit topic sentence: Excerpt 1 states its thesis in the opening sentence (anechoic tiles absorbing sonar and dampening vibrations), Excerpt 2 states its thesis in the central embedded sentence (semipermeable membranes extracting potable water), and Excerpt 3 delivers its thesis in the concluding synthesis sentence (ring laser gyroscopes providing drift-resistant inertial navigation without moving parts).
Step-by-Step Solution
Key Concept
Identifying Explicit Main Ideas Across Rotated Sentence Positions
Estimated Time:2m 0s