They appear larger than they really are.
        
                    
             
        
        
        
Answer:
Increase occur in skin diseases and decrease occurs in the Earth's average temperature.
Explanation:
If both Carbon Dioxide and Ozone levels began to decrease, increase occur in skin diseases and decrease occurs in the Earth's average temperature. The decrease in ozone levels allows more UV radiation to reach the Earth's surface which lead to various diseases such as skin cancer, cataracts, and weakened immune systems. The atmospheric carbondioxide gas is responsible for the increase of surface temperature by trapping reflected solar radiations so decrease in carbondioxide concentration will leads to lower surface temperature.
 
        
             
        
        
        
Answer:
The correct answer will be - Keystone species
Explanation:
Keystone species refers to the species present in a community which has a large effect or great influence on the surrounding environment.
The concept of Keystone species was introduced by the Robert T. Paine in 1969 to the species which help maintain the structure of the biological community.
The keystone species are called keystone species as its presence affect the other organisms directly and if removed from a community it will lead to the shift or change in the structure of the community.
Thus, Keystone species is the correct answer.