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26.4: D

Difficulty Level: At Grade Created by: CK-12
dead zone
area in the ocean or other body of water where low oxygen levels from excessive growth of algae have killed all aquatic organisms
deciduous plant
type of plant that seasonally loses its leaves to reduce water loss during the cold or dry season each year and grows new leaves later in the year
organism that breaks down the remains of dead organisms and other organic wastes
demographic transition
changes in population that occurred in Europe and North America beginning in the 18th century, in which death rates fell and population growth rates increased, followed by birth rates falling and population growth rates decreasing
extension of the cell body of a neuron that receives nerve impulses from other neurons
dependent variable
variable in a scientific experiment that is affected by another variable, called the independent variable
deposit feeder
animal that obtains organic matter for nutrition by eating soil or the sediments at the bottom of a body of water
dermal tissue
type of plant tissue that covers the outside of a plant in a single layer of cells called the epidermis
lower layer of the skin that is made of tough connective tissue and contains blood vessels, nerve endings, hair follicles, and glands
decomposer that consumes detritus
substance composed of dead leaves, other plant remains, and animal feces that collects on the soil or at the bottom of a body of water
medical procedure in which blood is filtered through a machine in patients with kidney failure
large, sheet-like muscle below the lungs that allows breathing to occur when it contracts and relaxes
process by which unspecialized cells become specialized into one of many different types of cells, such as neurons or epithelial cells
type of passive transport that does not require the help of transport proteins
process of breaking down food into nutrients that can be absorbed by the blood
digestive system
organ system that breaks down food, absorbs nutrients, and eliminates any remaining waste
having two of each type of chromosome
directional selection
type of natural selection for a polygenic trait in which one of two extreme phenotypes is selected for, resulting in a shift of the phenotypic distribution toward that extreme
movement of offspring away from their parents
disruptive selection
type of natural selection for a polygenic trait in which phenotypes in the middle of the phenotypic distribution are selected against, resulting in two overlapping phenotypes, one at each end of the distribution
DNA (deoxyribonucleic acid)
double-stranded nucleic acid that makes up genes and chromosomes
DNA replication
process of copying of DNA prior to cell division
taxon in the revised Linnaean system that is larger and more inclusive than the kingdom
dominant allele
allele that masks the presence of another allele for the same gene when they occur together in a heterozygote
state in which a plant slows down cellular activity and may shed its leaves
double helix
double spiral shape of the DNA molecule
drug abuse
use of a drug without the advice of a medical professional and for reasons not originally intended
drug addiction
situation in which a drug user is unable to stop using a drug

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Date Created:

Feb 23, 2012

Last Modified:

Oct 07, 2015
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