Given the age of the meteorite is 4.5 billion years old with 78 atoms of lead-206 the answer should be B. 156. The half-life of uranium-238 in order to decay into lead-206 is 4.46 billion years, which means that the original number of atoms is 156.  
        
             
        
        
        
Answer:
a."Alkylating agents are toxic to tissues that have rapidly dividing cells."
Explanation:
In the given example the patient is about to begin chemotherapy with a bifunctional alkylating agent. 
when the two dna strands are cross linked they will not separate for dna replication which will halt the cell division process so rapidly dividing cells will stop dividing and die
Moreover,Chemotherapeutic agents, also known as antineoplastic agents, are used to prevent the growth of fast-growing cells, usually in the sense of malignancy, directly or indirectly.
Therefore, Chemotherapeutic agents are Alkylating agents that are toxic to tissues that have rapidly dividing cells
So, this statement by student indicates an understanding of his chemotherapeutic agent. 
 
        
             
        
        
        
The answer should be 2 because planting trees gives out oxygen and we need oxygen to live
        
             
        
        
        
Answer:
True
Explanation:
That's why modern-day farmers use giant sprinklers and tractor water tanks and trucks!
Glad I could help!!
 
        
                    
             
        
        
        
Answer:
1. Birds in the chaparral biome have adapted to living (C)on the ground.
2. The aromatic oils of chaparral shrubs: All of the above
Explanation:
1. birds are adapted to live on the ground and prey during night time.