$1.$ The application of $\_$ in the design of helical springs significantly impacts their $\_$ and $\_$ under loads, especially in precision engineering where the $\_$ of the spring is critical. $($Options: advanced materials, geometry modifications, pitch variation, stiffness, durability, accuracy$)$

$2..$ In the development of springs for acoustic applications, minimizing $\_$ is a key goal. Materials and designs that reduce $\_$ and $\_$ are preferred to ensure silent operation in devices like $\_$ and $\_\_\_.($Options: noise, vibration, resonance, musical instruments, precision scales$)$