Paleozoic shells, which do not fizz in acid, are probably recrystallized from the original aragonite to calcite (except for echinoderms, which are originally calcite). true false

Advances in technology have enabled scientists and researchers to better study the evolutionary relationships between species

(select all the correct choose each statement that is scientific. - the opinions of randomly selected participants in a survey prove the idea that global temperatures are not increasing on earth. - the universe's average temperature and rate of expansion support the idea that it began as one super-dense and hot mass 13.8 billion years ago. - ocean tides are caused by the uneven gravitational pulls of the moon and sun on different parts of earth. - human life is more valuable than other forms of life on earth because humans are more intelligent than other organisms.

People with one sickle cell allele are not likely to get malaria. what is this an example of?