Which vitamin is essential in early pregnancy to prevent nervous system defects such as spina bifida, which is characterized in the fetus by incomplete closing of the backbone and membranes around the spinal cord mastering biology?

Organisms are classified, or grouped into categories, based on similarities in their characteristics and/or evolutionary relationships. the study of how organisms are classified is known as

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.

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