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The answer is d I'm pretty sure because the second one and the first one don't make sense but I'm not 100 percent positive about it not being d ..... sorry if it's wrong.
Explanation:
Percentage composition of oxygen = (80/134) * 100% = 59.7%.
Radiography techs are trained to operate medical equipment that uses X-rays and other types of radiation. Ultrasound techs, referred to professionally as diagnostic medical sonographers, operate equipment that uses high-frequency sound waves to create images.
(Credits to google)
