The outer coverings that are tough but, flexible provided protection to the land plants.
Answer
decomposers end the food chain but technically the food chain never stops
Carbon is the only element that can form so many different compounds because each carbon atom can form four chemical bonds to other atoms, and because the carbon atom is just the right, small size to fit in comfortably as parts of very large molecules. ... They can even join "head-to-tail" to make rings of carbon atoms.
The right answer is glutamate
Glutamate is a major excitatory neurotransmitter associated with learning and memory.
It is also associated with Alzheimer's disease whose first symptoms are felt in memory.
Most people unknowingly consume monosodium glutamate (MSG), a commonly used food additive.
An experiment was done on healthy patients, giving them 12 grams of glutamate. It was found that the experience led to headaches, nausea or jaw pain in 50-60% of cases.
It was also measured the level of glutamate contained in the muscles of patients with jaw problems. The tests concluded that the most painful muscles were those containing the highest levels of glutamate.
According to him, one of the keys to chronic pain could lie in the development of drugs that reduce the rate of glutamate.
