Students. Which of the aspects of user-machine interface aspects found in Chapter 3 do you believe is most causal of worker error or incidents. You can use any of the items found in Chapter 3. Please provide examples of how and why you believe this is the case? So please answer this question. 2# Also please respond to these two student (Without a strong critique please) : ١- Restrict number of function keys, I think this aspect is one of the best effective change in the workplace because it makes most of the machines be easily to use without any mistakes and make the work an ergonomic during work. In addition, old machines have many buttons on it and some of the keys have the same color, so during fast work the employees could use wrong keys because there are a lot of keys with the same color. In these days the new machine use by computer, so you can avoid the mistake and wrong buttons. Old keys were beside each other and that also another mistake design, also same level and this could make employees click it by mistake. Moreover, some machines have the (start/off) buttons beside move position and this could make the change the sizes of the products such as some of old milling, lathe, and boring machine, etc. On the other hand, new generation machine are more ergonomic with the flexible system and less keys and this make the work more productive and easy.