Credit to @tokyo_timeslip
One of the rationales of sane people regarding alternative energy sources is the cost of using "more expensive" energy sources when cheap (at least for the time being), albeit more polluting, alternatives like coal and natural gas are readily available.
The argument is that if Country A switches to full renewables, in the time it takes for the prices to become low enough to be competitive against coal, Country B, which is unscrupulous in its development and continues using coal as its main energy source, would gain a significant advantage over Country A.
You could even argue that for Country B, switching to alternative energy sources would be unfair, considering that Country A enjoyed decades of rapid growth and development using cheap coal, whereas Country B would not. Since Country A won't fully switch to alternative energy sources to maintain its supremacy, and Country B won't change for the sake of its development, we're effectively in a deadlock.
Personally, I think all countries should work together and switch to renewable energy sources to reduce the impact of climate change. Unfortunately, the world is not so simple, and the conflict is more nuanced than simply "keeping profits vs. creating a better world."
In my experience, this is because they conduct yearly x-ray examinations to detect tuberculosis and other lung diseases. Shirts and bras interfere with the image, so they ask students to bring a plain shirt to wear during the examination. However, if there's no other option, they may ask them to do the examination bare-chested. In my case, there was gender separation (not only in location but also in the time frame), but I can't say the same for all schools or age groups. Japanese schools are known for having students change into sports clothing in the classroom without gender separation up to 3rd or 4th grade, so I wouldn't be surprised if there are schools that don’t separate genders for medical examinations.