Why are the constitution frequently changing explain any 4 reasons ​

The symbols found on the map below indicate where fossils have been found in the same layer of sediment. each unique symbol represents fossil locations of a particular species.

Aresearcher conducts a focus group to learn about attitudes towards hygiene and disease prevention. two weeks after the focus group, the researcher learns one of the subjects had a heart attack at home and was hospitalized, but made a full recovery. based on dhs regulations, the researcher report this event to the irb? no, this does not need to be reported since the subject had the heart attack when they were home, not at the focus group. no, this does not need to be reported since it is unrelated to participation in the study. no, this does not need to be reported because two weeks have passed. no, this does not need to be reported since the subject recovered.

The second westward surge reached the: mississippi river, appalachian mountains, oregon territory