In observing epithelial cells under a microscope, the cells are arranged in a single layer and look tall and narrow, and the nucleus is located close to the basal side of the cell. The specimen is what type of epithelial tissue?

Columnar epithelial tissue.

Explanation:

The above scenario confirms that these are simple columnar epithelial tissue because columnar cells are tall, narrow and nucleus in the tall column like cells located at the basal end of the cells. Columnar epithelial tissue are responsible for absorption and secretion of molecules. These are present at some part of digestive tract, female reproductive tract, and respiratory system.

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.