Answer: Aqueducts
Explanation: They were first developed around 312 B.C., these engineering marvels used gravity to transport water along with the stone, lead and concrete pipelines and into city centers. Aqueducts liberated Roman cities from reliance on nearby water supplies and proved priceless in promoting public health and sanitation.
Maarten Schmidt found the spectral lines were high redshift (had their emission lines shifted toward longer, redder wavelengths by the expansion of the Universe)
<span>The puzzle about quasar spectra, which was finally solved by Maarten Schmidt, was </span><span>the brightest known quasar</span>.
Biological warfare, also known as germ warfare, is the use of biological toxins or infectious agents such as bacteria, viruses, insects, and fungi with the intent to kill, harm or incapacitate humans, animals or plants as an act of war.
