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Take the output of the LM35 and feed that to the input of a couple of 741s configured as a comparator.
Configure the comparator with a lower range equal to the LM35's output at 34 degrees, an upper limit of 39 degrees and the hysterisis equal to voltage difference between the two (which can be very tight or very loose).
Take the outputs to the two 641s, run them, individually, each through a its own diode, tie the diode outputs together and you'll have an "on/off" signal ("on" at 35 degrees and "off" at 39 degrees) to trigger whatever you want to trigger.