About 530 million years ago, an evolutionary period known as the "Cambrian explosion" took place. Large numbers of new animal species appear in the fossil record that corresponds with this time. Based on patterns of extinctions documented in the fossil record, about how many of these Cambrian species are probably still surviving today?

A- none of them
B- All of them
C-most of them
D-A very small number of them

Why did the federal government end its support of yucca mountain as a site for long-term storage of nuclear water

The serengeti plains are part of the african savanna ecosystem and are home to a variety of different species of plants and animals. the serengeti plains experience a seven-month period of seasonal drought each year, during which the ecosystem receives only four inches of rain and the availability of some resources becomes very scarce. which type of limiting factors does the seasonal drought in the serengeti plains affect?

Homo heidelbergensis was a tall, muscular hunter, who used both tools and weapons. because h. heidelbergensis was not a gatherer/forager, but ate a varied diet including meat and fish, we would expect to see what anatomical changes?