Dated to approximately 500,000-400,000 years ago, the site of has yielded a sample of 4,000 fossil fragments representing about 28 premodern homo sapiens individuals, more than 80% of all middle pleistocene hominin remains in the world.
a. steinheim
b. ehringsdorf
c. sima de los huesos
d. petralona
e. swanscombe

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.

The negative impacts of nonnative species generally outweigh the positive impacts

In which state was more than 100 billion tons of coal mined in 2005?