Which of the following might a scientist cite as a reason for the Cambrian explosion? A. Lower oxygen levels in the oceans.
B. Heightened diversity of fossils.
C. Heightened availability of minerals in the oceans.
D. Lowered predation leading to better survival of species.

In natural selection, what is actually “selected? ” a) alleles are directly selected b) genotypes are directly selected c) phenotypes are directly selected d) entire populations are directly selected

For a to be healthy, it has to have lots of different kinds of plants and animals. all of the different types of plants and animals in an ecosystem. name four types of ecosystems from those listed in the video. b) c) d) most living things live here. all living things depend on how an ecosystem like a game of sticks? why should we build new buildings on existing land? name four extinct species from those listed in the video. b) c) d) the best way to wipe out a species is to the largest ecosystem in the world is this percent of the world is covered by water. how many of all species in the world live in the ocean? list five things you can do to increase biodiversity. b) c) d) e) how many species are we losing per hour?

Which heredity condition causes a buildup of mucus in lungs and pancreas? a. cystic fibrosis b. heart disease c. huntington's disease d. sickle cell anemia