Question

in the digital age, computers and cell phones offer an endless stream of stimuli. due to constant email alerts and text messages, people are losing the ability to focus on a single task. an experimental eyeglass system called narbis hopes to change that. the eyeglasses come with a headset that uses sensors to measure the wearers brain activity. when the wearer loses concentration, the glasses darken, and thus the wearer cant see. the brain naturally attempts to clear the glasses, and in the process, learns to focus. narbis is based on a method called neurofeedback, a type of brain training. in neurofeedback, your brain waves are shown to you in real time so you can learn to focus them in desirable ways. match causes with their effects. neurofeedback reveals your brain waves. the glasses darken. technology is a distraction. cause effect concentration is difficult. the wearer cant see.

Explanation:

• The text states constant tech stimuli (email alerts, texts) make focusing hard, so "Technology is a distraction" causes "Concentration is difficult".
• The glasses darken when the wearer loses concentration, so "The glasses darken" causes "The wearer can't see".
• Neurofeedback shows brain waves in real time, and the text links this to learning to focus (though the given effect options are limited, this is contextually the purpose).

Answer:

Technology is a distraction → Concentration is difficult
The glasses darken → The wearer can't see
Neurofeedback reveals your brain waves → (Contextually: Learning to focus, but based on the match task structure with given options, the above two are the direct matches from the text)

(Note: The task likely expects the two clear direct matches from the text: "Technology is a distraction" to "Concentration is difficult" and "The glasses darken" to "The wearer can't see".)