E. coli are a species of bacteria. Like all bacteria, they have a round piece of DNA that contains most of their genetic information, but also plasmids, that contain some more. Plasmid can be passed on from bacterium to bacterium and they contain information for fighting antibiotics. Tetracycline is such an antibiotic. The process of putting a plasmid inside a bacterium is called transformation. So what the above sentence really says, is that a bacterium just got a plasmid that is probably holding the genetic information to produce proteins that fight antibiotics like tetracycline. While regular strains of E. coli might not be able to deal with tetracycline, transformed strains will probably be able to survive it. Hence, the culture will have live bacteria and the bacteria that have a plasmid against tetracycline will be favored and survive.
Because ounce and inch system are too big thus less sensitive. Using metric systems like milliliter and millimeter might be better since you can find smaller differences. If you are using a system that less sensitive you can observe small differences and might need to grow the trees bigger than it should.
Hands have a larger range of dexterity compared to feet. Longer tendins and stronger grip strength, they are made for more intrucite tasks such as making and using tools. Feet have a larger surface area, made for holding large amount of weight, shorter bones and tendins allow for easy acceleration and no extra flesh to get in the way. Other more primitive species will not have the feet we have due to evolution. They simply do not have the evolved sense of brain pwer hians haev in order to make tools. So they have more need for speed, grip exc. in feet to escape pradators and live day to day. Where on the other hand humans do not.