Questions & Detailed A+ Answers
< (Latest 2025 Edition | Objective Assessment
Study Guide) >
Non-living, may be within or made by a living organism. - ANSWER Abiotic
Living. Matter is considered ______ if it was ever alive at some point in time - ANSWER
Biotic
Smallest level. The basic unit of matter. Consists of a dense nucleus surrounded by electrons. -
ANSWER Atom
,Second level. A chemical structure consisting of at least two atoms held together by a chemical
bond. - ANSWER Molecule
Third level. Biologically important molecules that are technically polymers. Example: DNA. -
ANSWER Macromolecule
Fourth level. The fundamental unit of life. Essentially a tiny droplet of water and other
molecules enclosed by a fluid "skin" or membrane. The smallest and simplest entity that
possesses all the characteristics of life. - ANSWER Cell
Fifth level. Compartments inside the cell that contain specific groups of macromolecules and
carry out specific cellular functions. One of these organelles is the nucleus; it encloses the DNA
within the cell. - ANSWER Organelle
Sixth level. Single-celled life form. Consists of just one cell and include unicellular organisms
such as bacteria and protists. - ANSWER Microorganism
Seventh level. Formed when similar cells work together to fulfill the same detailed function. -
ANSWER Tissue
,Eighth level. Collections of tissues that work together to carry out a common general function.
Present not only in higher level animals but also in plants. - ANSWER Organ
Ninth level. Consists of functionally related organs. Mammals have many. - ANSWER Organ
System
Tenth Level. Individual living entities that survive and reproduce as a unit. For example, each
tree in a forest. - ANSWER Organism
Eleventh level. Consists of all the individuals of a species living within a specific area. - ANSWER
Population
Twelfth level. Populations can interact with each other in positive and negative ways, and
together they form this. - ANSWER Community
Thirteenth level. Consists of all the living things in a particular area together with the abiotic, or
nonliving, parts of that environment. - ANSWER Ecosystem
, Fourteenth level. The highest level of organization in living systems. The collection of all
ecosystems on Earth. Includes all habitable zones on the planet, including land, soil, and rocks
to a great depth in the Earth's crust; water and ice; and the atmosphere to a great height. -
ANSWER Biosphere
Characteristics of a system that are not present in any of its component parts. - ANSWER
Emergent Properties
The scientific study of life and is the branch of science that studies living organisms and the way
organisms interact with their environments. - ANSWER Biology
The ability or tendency of organisms and cells to maintain stable internal conditions. - ANSWER
Homeostasis
Any matter an organism needs but cannot make for itself. - ANSWER Nutrient