Answer:
The small population of zooplankton have an unequal effect on the marine community.
Explanation:
According to this question, there are three trophic levels of organism in a lake as follows: non-native fish, zooplankton, and algae. However, due to the declination in the number of zooplanktons in the lake as they were fed on by the non-native fish, the algal population increased to form a BLOOM. 
This bloom of algal species can be attributed to the lack of zooplanktons, which represented the only herbivorous (plant eaters) organism in that community. Hence, their relatively small population have an unequal effect on the marine community. This means that the small population of zooplanktons caused an imbalance in the community and this is why ZOOPLANKTON is the keystone species in this scenario.
 
        
             
        
        
        
Explanation:
The dog salivating is an example of responding to stimuli
 
        
             
        
        
        
Answer:
The correct answer is option c. 
Explanation:
In the Barro Colorado Island, the mentioned local population of the butterfly species went on to become extinct mainly due to the fragmentation of habitats and the loss of habitats. The host plant on which the butterflies fed could not grow and they started to decline in number and slowly became extinct. Due to this the species of the butterfly also would have got extinct because of the lack of food.
 
        
             
        
        
        
Answer:
Hypothalamus 
Explanation:
The Hypothalamus is located below the cerebral cortex. It's involved with basic functions like eating, sex, temperature control, sleep, aggression. It's main function is to produce sex, growth and stress related hormones carried down axons to the pituitary gland. When carried out, it's then released into the bloodstream to activate and organize distant body systems.