A or C 
Explanation:
Gas does not have a volume correct me if im wrong 
 
        
             
        
        
        
Answer: a. Measuring the amount of rain that falls in a 24-hour period in a rain gauge.
 
        
             
        
        
        
Depending on the organism, the cell can get its energy from the sun (Plant; Photosynthesis) or through ATP energy (Animal). 
        
             
        
        
        
  <span>They do not possess any skeleton at al</span>
        
             
        
        
        
Answer: 
1. Substitution 
2. Insertion and deletion 
3. Amino acids can have more than one codon that signals for it. Due to this, some substitutions don’t affect the protein at all. 
Explanation: 
1. Substitution sometimes isn’t as impactful. It can result in the same amino acid to be signaled as the original one since amino acids can have more than one codon signaling for it.
2. Insertion and deletion are also known as frameshift mutations. This is because they shift the codon spots by adding or deleting a nucleotide.