1) means of passive protection: stinging hairs (nettles), thorns or thorns (blackberries, thorns);
2) chemical protection agents that make plants inedible or slightly edible, for example, milky juice (celandine), resin (conifers); also, some plants release phytoncides into the environment – volatile biologically active substances that protect plants from pathogens and fungi (garlic, onions, mustard, etc.).
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.