eras

The period of geologic time beginning 245 million years ago and ending 65 million years ago; the age of the dinosaurs and cycads, the Mesozoic falls between the Paleozoic and ...

Era Industrial

Anthropology; Cultural anthropology

A cultural stage characterized by the first use of complex machinery, factories, urbanization, and other economic and general social changes from strictly agricultural societies.

núcleo del átomo

Biology; Cell biology

An atom's core; contains protons and one or more neutrons (except hydrogen, which has no neutrons).

número atómico

Biology; Cell biology

The number of protons in the nucleus of an atom.

asma

Biology; Cell biology

A respiratory disorder caused by allergies that constrict the bronchioles by inducing spasms in the muscles surrounding the lungs, by causing the bronchioles to swell, or by ...

ascomicetos

Biology; Cell biology

Division of fungi that contains the yeasts and morels; ascomycetes produce an ascus (or sac) in which ascospores are produced.

selección artificial

Biology; Cell biology

The process in which breeders choose the variants to be used to produce succeeding generations.

reproducción asexual

Biology; Cell biology

A method of reproduction in which genetically identical offspring are produced from a single parent; occurs by many mechanisms, including fission, budding, and fragmentation.