What is a type of research that involves observation and collecting data but does not include control

What two layers don't S waves travel through

What is one criteria that must be met in order for an ecosystem to be stable

Which occurrence most likely led to the other three? (1) Human population growth reached 6.8 billion in 2010 and it continues to increase. (2) The number of African elephants has declined from 1.2 million in 1979 to about 20,000 today.

What is the greatest use of groundwater? a. drinking b. industry c. agriculture d. recreation

When antibodies are produced by lymphocytes, the body is conducting adaptive, passive, or innate immunity.

Forensic odontologists might be involved in which of the following circumstances? A femur bone is found in a field. A victim has a bite on his arm. A profile of a suspect is needed. Beetles are collected from a decomposed body.

Why does hurricane season occur from late spring through fall in the Atlantic region? A. Hurricanes need warm oceans waters to form B. hurricanes need the high air temperatures to form to form. C.

Earth's most recent era is the

During what process is water produced

Water, fuel, food, and raw materials are examples of what? A. regulating services B. cycling of matter and energy C. natural resources. D. cultural services