The correct term to fill in the blank would be cortisol. In the context of stress hormones and the brain, cortisol has a profound effect on the hippocampus, a brain structure that plays a pivotal role in memory. Cortisol is classified as a steroid hormone which is produced by the adrenal gland. It is deemed as the stress hormone as it is released as a response to stress as part of the fight or flight process. From studies, cortisol was found to have effect on the hippocampus when present in high levels. It damage and kill the cells in that area of the brain. The hippocampus is the area of the brain that is responsible for the long term memory storage. So, when this part is damage then the storage for our memories would surely be affected.
To answer this question, let us first mention what is food danger zone. Well, this refers to the temperature range in which bacteria grows faster in the food. The range is defined as 30 to 140 degree Fahrenheit or can be converted into 4 to 60 degree Celsius. Going back to the question, the maximum number of hours that a food can be held in the food danger zone is only 2 hours. Beyond this 2 hours, the food is not safe to be eaten and the person who dares to eat this food might get some illness and worst might experienced food poisoning.
Other reasons are
Not finishing the antibiotics.
Or
Taking antibiotics too often
You can do golden rice. It was genetically modified to produce beta carotene, which rice does not usually have. When metabolized by the body beta carotene is turned to vitamin A which is essential to human vision, immune systems, and healthier skin
I want to say individuals more so than entire populations. That being said it's because the entire populations of living things are able to evolve and move forward through slow evolution.
