Why are most modern constellations composed of faint stars or located in the southern hemisphere?

Astronomers from areas in the northern latitudes developed different constellations and maps of the sky than their southern counterparts, as faint stars weren't visible to them. In the 18th and 19th centuries, there weren't constellations in the southern hemispheres, so astronomers, instead, invented them.

Mexico has a host of environmental problems, including significant chemicalpollution  from factory discharges and waste dumping, but the main threat to itsbiodiversity  probably stems from  deforestation  and other natural habitat losses. forest habitat is lost for a number of reasons