Complex sentence: The frill-necked lizard is ectothermic and maintains its body temperature by basking for up to 30 minutes to achieve an average of 2--3 ° C above the surrounding temperature.
Split into simpler sentences: The frill-necked lizard is ectothermic and maintains its homeostatic body temperature by basking for up to 30 minutes. This achieves an average of 2--3 degrees Celsius above the surrounding temperature.