Why are fossils from the cenozoic era, which began 65 million years ago, the easiest to find?
a. the number of species greatly increased during this era.
b. life on earth, in the form of cyanobacteria, began during this era.
c. fossils of the largest creatures are from this era.
d. fossils from this era are found in layers closest to earth’s surface.

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.

The eruption of a nearby volcano causes a prairie ecosystem to receive a lot less sunlight. which of these is most likely effect on the ecosystem?

Who discovered tuberculosis bacteria?