Distribution of phenotypes within a population may be impacted by different types of natural selection. These types of selection include;
Directional selection involves a change in the environment shifts of phenotypes observed. Example is the giraffe neck-length, where the length got longer and longer over time to reach the leaves at the top of trees.
Stabilizing selection , this is a selection where an average phenotype is favored. example is number of eggs laid by birds such that too many eggs will be a waste of energy because some chicks would starve.
Disruptive selection is a selection where individuals with an average value of a trait are affected most while those with values below average are affected least. Example small individuals are capable of hiding from predators while big individuals can not fit in the hiding place but instead will fight with predators.
        
             
        
        
        
A sample is termed REPRESENTATIVE SAMPLE  if it has similar characteristics to the population being studied.
The representativeness of a sample is the extent to which its characteristics accurately reflects the characteristics of the population being studied.
        
                    
             
        
        
        
Answer:
step 1: mRNA attaches to the ribosome
step 2: tRNA's attach to free amino acids in the cytoplasmic "pool" of amino acids
step 3: tRNA carries its specific amino acid to the ribosome
step 4: tRNA "delivers" its amino acid based on complementary pairing of a triplet code (anticodon) with the triplet code (codon) of the mRNA
step 5: Enzyme "hooks" the amino acid to the last one in the chain forming a peptide bond
step 6: Protein chain continues to grow as each tRNA brings in its amino acid and adds it to the chain
 
        
             
        
        
        
Answer: elastic fibers
Explanation:
Elastic fibres are the essential durable component present in mammalian connective tissueand functions to provide proper pulmonary,  cardiovascular and intestinal system structure and function. Their structural function is to provide elastic recoil and resilience for the tissues.
Elastin fibers ahve two main including microfibrils and elastin containing fibrillin play a mechanical and structural role in the arteries, and their important function is to provide the tissues with resilience and elasticity. 
Hence, elastic fibers helps arteries to adapt to changes in blood pressures that accompany the heartbeat.