Answer:
The hole is lack of knowledge of the concept of natural selection, especially its physical properties and how it operates.That is what made those organisms with fitted traits to resit the selective pressures and therefore survive than others with less resistance .
Basically,he lacked the knowledge of the concept of variation as the driving mechanisms of natural selection he theorised. Darwin did not understand how variation among different species of organisms physically emerged to made these organisms resistant to the selective pressure, and therefore emerge as the survival of the fittest in the population.
Explanation:

Damage to the frontal lobe of the braineventually causes problems with intelligence, judgment, and behaviour. Damage to the temporal lobe affectsmemory. And damage to the parietallobe affects language. Alzheimer's is themost common form of mental decline, or dementia, in older adults.
Answer:
The answer is vertebrate.
Explanation:
Vertebrates are those animals that have a central spinal cord. Fish, Chicken and rabbit can be classified as vertebrates because they all have a spinal cord. The vertebrate is a big term that is further divided into different classes for example Fish, amphibians, mammals, avian, and reptiles,
People eat frogs and not trouts because if they eat trouts they would need one each day or 365 for the year.