viruses i think again sorry if this is wrong
Answer:
SA node
Explanation:
The SA node (called the pacemaker of the heart) sends out an electrical impulse. The upper heart chambers (atria) contract. The AV node sends an impulse into the ventricles. The lower heart chambers (ventricles) contract or pump.
The answer is B, bird flu. The other diseases have been around much longer than bird flu has. Bird flu has been in Asia since 2003, but didn't reach Europe and the middle east until 2005, making bird flu a very new disease.
The right option is OTEC
Ocean Thermal Energy Conversion (OTEC)
uses the temperature difference between deep cool ocean water and warm tropical
surface waters to produce electricity. Quantities of cold water that can be
used for air conditioning is produced as a by-product.
The answer is to your question "How many meters is 50 cm?" is 0.5m