whenever I'm trying to run my code I'm getting this notification that says serial was not declared in this scope, so please help me for this issue so quick.

readme.txt Arduino 1.8.13 File Edit Sketch Tools Help readme.txt double temp = 1 / (0.001129148 + (0.000234125 + float tempc = tempK 273.15; temp = (tempc * 9.0)/ 5.0 + 32.0; serial.print (tempc); serial.print('\t'); runMillis = micros(); serial.println(runMillis); delay(1000); } Done Saving exit status 1 'serial' was not declared in this scope 7 Arduino Uno on COM4