21.
									
										Restriction fragments length polymorphisms (RFLPs)
									
								
															
														
																									
										A:
											Are used to determine the position of restriction sites in a genome
									
																										
										B:
											 Are used in physical mapping
									
																										
										C:
											 Are used in genetic mapping  
									
																										
										D:
											Usually occur as multiple (more than 2) alleles in a genome 
									
																								 
							
																
									The answer is:
										C
									
								
														
							
								
								
							
							
							
								