_________ is the only element capable of forming stable, extended chains of atoms bonded into single, double, or triple bonds. Hydrocarbons containing carbons which are bonded by only single bonds. Hydrocarbons containing at least on Carbon-Carbon bond which is a double bond.
There is no defined limit on the capacity of the brain. The brain's capacity cannot be measured as it is not subject to a defined "space" where the memory is kept, and it is not such that each neuron is responsible for a single memory. The brain has complex mechanisms of memory storage, that even improve if trained.
Answer:
Possession of inherited adaptations that maximize fitness.
Explanation:
Basically ones that are best adapted for their environment. (I'm assuming "he" is Darwin?)