What two land-uses were contributing excess nitrogen to the watershed and what event washed these excess nutrients into the river?

What is thought to have caused the mass extinction at the end of the cretaceous period?

Which organisms have pharyngeal arches that develop from all three germ layers and go through the same development stages as embryos? 1.bird 2.ladybug 3.starfish 4.snake

Which of these is most likely to happen if parallax measurements of star distances are taken after a gap of six months? the results would be accurate the results would be inconsistent the results would not be valid the results would not be repeated