Nitrogen fixation, the conversion of N2 to NH3, is an ecological service provided primarily by:

In a cladogram, a “node” represents a common ancestor shared by the descending clades.

Michael, a 19 year-old male, presents to the clinic with a complaint of diffuse lower abdominal pain that has progressively worsened over the last few days. He states that he has experienced nausea and vomiting as well. The next step in the health assessment process would be to:

 Cyanobacteria are responsible for the “Great Oxygenation Event” in Earth’s history.

Put these events in the correct chronological order: (1) Origin of eukaryotes, (2) Photosynthesis, (3) Multicellularity, (4) Origin of life.

The nurse educator is teaching undergraduate nursing students about the immune response. He explains that which of the following white blood cell types is typically elevated during an acute bacterial infection?

The earliest prokaryotic life, in microbial mats, likely emerged:

Gram-positive bacteria stain purple because:

Protocells, the precursors to life, were likely capable of simple metabolism and maintaining an internal chemical environment different from their surroundings.

Which domain of life is characterized by having peptidoglycan in its cell walls?