9.
									
										The biological role of restriction enzymes is:
									
								
															
														
																									
										A:
											Restrict the damage to DNA by ultraviolet light 
									
																										
										B:
											Make bacteria resistant to antibiotics 
									
																										
										C:
											Degrade foreign DNA that enters a bacterium
									
																										
										D:
											 Restrict the size of DNA in certain bacterium
									
																								 
							
																
									The answer is:
										C
									
								
														
							
								
								
							
							
							
								