what is meaning of && sign here ?

if res>=120 & res<=200
                                                              if res_2>=480 & res_2<=600
                                                                  P_1='PERSON IS HEALTY';
                                                                  disp('PERSON IS HEALTY')
                                                              elseif res_2<450 && res_2>430
                                                                      P_1='PERSON IS SUFFERING FROM TACHYCARDIA';
                                                                      disp('PERSON IS SUFFERING FROM TACHYCARDIA')
                                                              elseif res_2>450 &&  res_2<480
                                                                      P_1='PERSON IS SUFFERING FROM BRADYCARDIA';
                                                                      disp('PERSON IS SUFFERING FROM BRADYCARDIA')
                                                               else
                                                                  P_1='Not Clear in ECG Signal';
                                                                  disp('Not Clear in ECG Signal')
                                                              end
                                                          end
                                                          if res>200 
                                                                  P_1='PERSON IS SUFFERING FIRST DEGREE HEART BLOCK';
                                                                  disp('PERSON IS SUFFERING FIRST DEGREE HEART BLOCK')

                                                            end

Answer 1

[Walter Roberson]

https://www.mathworks.com/help/matlab/ref/logicaloperatorsshortcircuit.html