The landscape in which limestone is eroded to form deep valleys and cavers are called Karst landscape or karst topography. This kind of development start occuring whenever the acidic water starts breaking down the bedrocks near the cracks. As the bedrock starts breaking down slowly, the cracks start to open up creating bigger holes. with passage of time the holes will become big enough to create an underground drainage system for the surface water to flow and form underneath. If the water is unable to flow out and becomes stagnant, then the Karst will start getting bigger.  
        
                    
             
        
        
        
Answer:
The answer is A
By the late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory. The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
 
        
                    
             
        
        
        
Answer: Codon
Explanation:
Codon refers to nucleotide triplets of mRNA that serve to specify the amino acid sequence of proteins. There are total 64 genetic code that specify 20 standard amino acids found in proteins. All codon together make genetic code. For example: AUG is codon that specify amino acid "methionine". AUG codon also serve as initiation codon during initiation of protein synthesis. 
 
        
                    
             
        
        
        
Answer:
The best answer to the question: What is the most likely explanation for this observation, would be, B: RNA processing removes the different segments from the mRNA molecules of each person prior to translation.
Explanation:
In order for cells to work, they depend on one of the four major macromolecules; proteins. These proteins are the messengers that carry out genetic commands from the DNA and they will ensure that all processes, including transcription and translation of new proteins, are carried out correctly. In order to produce proteins, the first step is for the DNA to be transcribed into mRNA, a nucleic acid that carries out the information on the DNA for protein generation. Once transcription stops, mRNA undergoes a series of clipping and reorganizing steps that will ensure that when it is decoded for protein formation, the process will be successful. These control steps are all part of the RNA processing mechanism that enures mRNA will successfully be translated into working proteins. 
The reason why from genes of different people, a very similiar protein chain may result, is also explained from the fact that codons (a grouping of three nucleotides present in mRNA), when read by ribosomes, and coupled by tRNA, can pair these codons with similar amino acids. Thus, one codon, or similar codons, may code for a singular amino acid. However, mechanisms in the cells prevent these kinds of anomalies, by repairing the mRNA sequence before it is translated into protein.
 
        
             
        
        
        
Answer:
1. lungs
2. skin
3. large intestine 
Explanation:
lungs inhale oxygen
skin is on the outside of the body
the large intestine processes your food into feces