Standard temperature and pressure (STP) is defined as 273 K and 1 atm.

The standard unit of time in the SI system is the second (s).

DNA is described as a double helix, consisting of two strands that wind around each other.

DNA is composed of nucleotides, which include a sugar, phosphate, and nitrogenous base.

A bisexual flower contains both male (stamens) and female (pistils) reproductive structures.

A bisexual flower contains both male (stamens) and female (pistils) reproductive structures.

An organism with two identical alleles for a trait is called homozygous.

The genetic makeup of an organism is referred to as its genotype.

Endangered species are those that are at risk of extinction due to various factors.

Endemic species are those that are found nowhere else on Earth and are often vulnerable to extinction.

Endemic species are those that are found only in a specific geographic area.

Excitability refers to the ability of a muscle to respond to a stimulus, such as a nerve impulse.

Excitability refers to the ability of muscles to respond to stimuli, such as nerve impulses.

Inflorescence refers to the arrangement of flowers on a stem.

Sublimation is the process where a solid changes directly into a gas without passing through the liquid state.

Sublimation is the process where a solid changes directly into a gas without becoming a liquid.

The neuromuscular junction is the synapse between a motor neuron and a muscle fiber, facilitating muscle contraction.

Embryogenesis is the process of development of an organism from a fertilized egg.

Cytokinesis is the process that divides the cytoplasm of a parental cell into two daughter cells.

The energy required to change a substance from liquid to gas is called the latent heat of vaporization.

Adaptive radiation is the evolutionary process where one ancestral species diversifies into multiple species to adapt to various environments.

Internal respiration refers to the exchange of gases between the blood and body cells, where oxygen is delivered and carbon dioxide is removed.

Local extinction refers to the extinction of a species in a specific habitat while it still exists in other areas.

Local extinction refers to the extinction of a species in a specific habitat while it still exists in other areas.

The pistil is the female reproductive part of the flower, consisting of the ovary, style, and stigma.

The pistil is the female reproductive part of the flower, consisting of the stigma, style, and ovary.

The fertilized egg is called a zygote, which is the initial stage of development before it becomes an embryo.

Speciation is the process through which new species arise from existing species due to evolutionary changes.

Speciation is the evolutionary process by which new biological species arise.

Fertilization is the process where the male and female gametes fuse to form a zygote.