A 400-mg sample of technetium-99m is used for a diagnostic test. If technetium-99m has an effective half-life of 4.8 hours, how much of the technetium-99m remains 72 hours after the test?
Express your answer to two significant figures and include the appropriate units.

What are the similarities of physical and chemical change ?

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

Chromosome 17 is made of over million base pairs.