Ultrasound frequencies are below 20 kHz and can be heard by humans.  

A thermos bottle minimizes heat transfer by radiation.

The refraction of light causes mirages due to frequency. 

The speed of sound increases as temperature decreases in air.  

The Curie temperature is the temperature below which a material becomes ferromagnetic.  

Please match the following concepts about antimicrobial resistance

Alternating current (AC) is used in homes because it is safer than direct current (DC).  

Significant figures are used to express the precision of measurements.

A hypothesis is a proven scientific fact.

Water expands when heated at all temperatures.