Answer:
question 1: 
- both the number of species and population density decreases as altitude above sea level increases
question 2:
increase in birth rate => greater number of young organisms
Explanation:
As altitude above sea level increases, O2 density decreases, the amount of UV rays increases and the difference between daytime and nighttime temperature increases
 
        
             
        
        
        
Answer:SECONDARY SUCCESSION Explanation:Secondary succession can happen after primary succession or independently of primary succession.An example of Secondary Succession by stages:
1. An area of growth.
2. A disturbance, such as a fire, starts.
3. The fire destroys the vegetation.
4. The fire leaves behind empty, but not destroyed soil.
5. Grasses and other herbaceous plants grow back first.
6. Small bushes and trees begin to colonize the public area.
7. Fast-growing evergreen trees and bamboo trees develop to their fullest, while shade-tolerant trees develop in the understory.
8. The short-lived and shade-intolerant evergreen trees die as the larger deciduous trees overtop them. The ecosystem is now back to a similar state to where it began.
(Hope this helps)
 
        
             
        
        
        
Answer:
C. Taking blood samples from patients for research purposes
without consent
Explanation:
Generally, providers may not render medical services without the patient’s consent, unless performance of emergency, lifesaving care is necessary. Taking samples from a patient is a type of medical service; thus, state consent laws apply. In addition, providers may not disclose PHI without patient authorization.
It depends on the definition of unethical being used, however I think I am right. I'm in AP bio currently. Let me know what the answer is :) 
 
        
             
        
        
        
Keratin is an intracellular fibrous protein that gives hair, nails, and skin their hardness, strength, and water-resistant properties. The keratinocytes in the stratum corneum are dead and regularly slough away, being replaced by cells from the deeper layers 
Hope this helped!
Good luck :p
~Emmy <3
 
        
             
        
        
        
Answer:
A 
Explanation:
I think an untreated water can carry disease causing organisms and make people sick