most fungi, ascomycetes also reproduce asexually by the formation of nonsexual spores called conidia at the ends of filaments known as hyphae.

Assembling the Tree of Life program: This National Science Foundation program was created in 2004 with the goal of constructing the evolutionary history for all major lineages of life. The program supports efforts to classify all major groups of organisms and to reveal the pattern of historical relationships that would explain similarities and differences among them.

The program has three goals: (1) Creation and support of multidisciplinary teams of investigators to acquire and integrate molecular and morphological evidence on both extant and extinct organisms in order to resolve phylogenetic relationships of large, deep branches of the Tree of Life; (2) Research and development of tools for computational phylogenetics and phyloinformatics to improve assessment, predictive capabilities, and the visualization and navigation of the hierarchical structure in the Tree of Life; and (3) Outreach and education in comparative phylogenetic biology and paleontology.

Asymptomatic: Presenting no symptoms of disease.

Asymptomatic carriers: A person or animal that has contracted an infectious disease, but displays no symptoms yet has the ability to transmit it to others.

Bacteria: Microscopic, single-celled organisms that have some biochemical and structural features different from those of animal and plant cells.

Basidiomycetes: Any various fungi belonging to the phylum Basidomycota, bearing sexually produced spores on a basidium. All hyphae of basidiomycetes are divided into segments by septa and go through three stages of development.

Biofuel: Fuel produced from renewable resources, especially plant biomass, vegetable oils, and treated municipal and industrial wastes.

Biological invasion: The process by which species (or genetically distinct populations), with no historical record in an area, breach biogeographic barriers and extend their range.

Bioluminescence: Light produced by a chemical reaction that originates in an organism.

Biota: The animal and plant life of a given region.

Chronic: Relating to an illness or a medical condition that is characterized by long duration or frequent recurrence.

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