It is called the seed coat
        
             
        
        
        
Answer:
A. Carotene
Explanation:
It is an orange/red pigment which is seen during the fall.
 
        
             
        
        
        
Answer:
I would assume D
Explanation:
Tube 1 doesn't contain an organism so it can't be that one. Both a snail and a plant are considered an organism, and cellular respiration occurs in almost any organism's cells
 
        
             
        
        
        
Answer:Wildebeest are considered keystone species because their presence has myriad effects on the ecosystem, unlike those of any other species. Wildebeest are the "lawnmowers" of the Serengeti grassland. They keep grass short which in turn reduces the frequency of fires.