The prototype was a large sized drone powered by a conventional aviation fuel powered turbojet at speeds of about 200 km/h. The switch to hydrogen is theoretical, the hyperspeed (let alone supersonic) is just aspirational. And by aspirational I mean

1. Raise lots of grants and venture capital
2. Keep lots of scientists, engineers and management paid for many years
3. Give up in about 10 years and move on to new project

agrred. I am not sure that topical application will be totally effective as the bacteria can hide systemically, and it is not clear whether the enzyme can be administered say by injection without clearance and immune problems. Lots of things kill bacteria, (fire, acids etc) only a very few are useful in humans.

This. The modulus of elasticity is the force need to stretch something (hypothetically) 100% . Most things cant stretch 100% so you stretch it by say 1% and multiply the result by 100

Probably wrong, though cant get the original article due to paywall. This has been suggested before and is not needed, any autocatalytic process with a negative feedback loop (e.g. one enantiomer inhibiting production of the other or using the other as feedstock) will end up with just one enantiomer surviving.

Back in the day the key was weights. If two things combine to give a new substance that is heavier (say iron + oxygen to iron oxide) then it is obviously a compound. If a substance cleanly decomposes to two new substances, then the new substances are simpler and might be elements (say hydrogen peroxide to oxygen and water). After building up lots of these reaction it became clear that some things (e.g carbon) couldnt be decomposed into anything simpler and must be an element.

Muscle action depends on ions moving. If a fibre was too large it would take too long for the ions to diffuse or be pumped in and out. So muscle is faster by having lots of little fibres bundled than one big lump

I would broadly agree except on the density bit. Tar is not much denser than water but the key attribute is the size of the molecules. Larger molecules have more area to interact with each other, resulting in more attraction and slower motion (e.g. higher viscosity). Tar molecules are about 10-20 times bigger than water.

then the graphite overpotentials mean you use more voltage and less efficiency

Is this cause or effect? I would imagine having any mental disorder e.g. depression would make one less likely to exercise.

Hyperventilation can cause loss of CO2 from the blood leading to faint-headedness and panic. https://medlineplus.gov/ency/article/003071.htm#:~:text=Excessive%20breathing%20creates%20a%20low,such%20as%20bleeding%20or%20infection. Breathing into a bag increases the CO2 into the blood (as you are rebreathing old breath) and restoring the balance.

To continue - there are two main types of drugs - first small molecules (aspirin, speed, phenacetin etc). These molecules are generally too small for the immune system to see and dont have enough "docking" sites for the immune molecules to latch on to. Many modern drugs are big (e.g. proteins such as artificial insulin) and they are quite likely to generate immune responses if they dont look like what the body expects. They have lots of molecular sites for the immune molecules to grab and recognize. Often these molecules are "pegylated" by the chemists, surrounded by nonimmunogenic polymers that sheild the large molecule from the immune system.