Referring to the back or upper side of an organism, often used in anatomical terms.

The primary artery that carries blood from the heart to the rest of the body in vertebrates, located along the back.

Fins located on the back of fish and some other aquatic animals, typically used for stabilization and maneuvering.

A feature of chordates, a tube-like structure that runs along the back of the body, developing into the central nervous system.

The back or upper surface of an organism, often used in anatomical and zoological contexts.

The mechanism by which organisms balance the expression of sex-linked genes, ensuring that individuals with different sex chromosome compositions express those genes at similar levels.

The impact of the number of gene copies or alleles on the phenotype of an organism, where a higher number can enhance or alter the expression.

A type of chemical bond where two pairs of electrons are shared between two atoms, commonly found in organic molecules like alkenes.

A process in flowering plants where one sperm cell fertilizes the egg cell to form a zygote, while another sperm cell fuses with two other nuclei to form the endosperm.

The spiral structure of DNA, consisting of two strands coiled around each other, forming the fundamental shape of the genetic material.