To complicate matters, not all iron should be considered equal per units mass, some forms of iron are considerably more bio-available, and in general the forms provided as supplement on cereals in are on the low end of bio-availability.
Angular 4/5 is simply the continuation of Angular 2, so it's more like 2/4/5. The Angular router had been up to a major version 3 so they skipped Angular 3 as a whole in the interest of keeping all of the parts of Angular in version sync.
Starting with the latest version of Angular is generally the best idea, though you may be tied to earlier versions depending on what other modules you want to use. For example, the npm version of ng-bootstrap is still tied to Angular 4 (though one can easily build one that does from the github repo). I would recommend starting with ng-cli as most (older) books will start you off with some other build system (e.g., system-js, an older webpack plugin).
Exactly that, though, the placebo effect of interest would only be induced on people who haven't tripped.
That aside, and of course accepting that states induced by psilocybin and other substances are unobtainable by any other means, you are still nowhere near saying that these same substances can _reliably_ be used to treat depression. Furthermore, this course of treatment also needs to _reliably_ not make depression worse or trigger other types of anxiety that could trigger other medical conditions. Clearly, exactly what a aperson does under the influence of these substances can remarkably impact the results of the studies, so the techniques being used are being judged in these experiments just as much as the substances being used.
One shouldn't be dismissive of these studies, but also one should understand that the techniques used aren't the end-of-the-line in terms of potential these substances may have. on the other side of the token, we must also tread carefully. We must first do no harm!
This study is attempting to show that psilocybin is effective in treating depression, not effective in inducing a 'trip'. For patients who have never experimented with psychotropics, there may be a placebo effect when they are told they are given a psychotropic substance. While I agree that psilocybin and other similar substances can induce powerful mental states unreachable by other means, it does not follow that there exists a clinical path by which these drug-induced states can be used to treat depression in a reliable way.