Explanation: A superheterodyne receiver converts a desired radio frequency (RF) signal to a fixed Intermediate Frequency (IF) using a mixer and local oscillator. This IF signal is then amplified and processed. The issue arises when an external, undesired signal exists at or very near the receiver's internal IF frequency. If such a signal is strong enough, it can bypass the initial RF amplifier and mixer stages and directly couple into the IF amplifier. Because this signal has not gone through the mixer, its reception is not dependent on the tuning of the RF amplifier or local oscillator, which are designed to select and convert the *desired* incoming RF signal. This direct path means the receiver's normal tuning controls cannot effectively filter out or tune away from this unwanted signal, leading to interference that is difficult to suppress.