Stars, dust, and stellar remnants are bound together by gravity to form a ____.
galaxy
The ____ gases are a group of chemical elements characterized by their low reactivity.
noble
The living organisms in an ecosystem are ____ factors.
biotic
Energy from the cell is generated by the ____.
mitochondria
Plant life is supported by a mixture of organic matter and minerals called ___.
soil
The eight ____ is a cycle that repeats every 29.5 days.
phases of the Moon
____ is an alkaline earth metal and mineral that is needed by the body for bone health.
calcium
“____” animals are animals whose body temperatures are dependent on their external environments, as they cannot generate internal body heat on their own.
cold-blooded
____ is a microscopic, single-celled organism that is destroyed by a class of medicine which includes penicillin.
bacteria
____ are large slabs of Earth’s outer crust that move independently.
tectonic plates
____ are regions in space where an enormous amount of mass is packed into a tiny volume.
black holes
The first element of the periodic table is ____, which is also the most abundant element in the universe.
hydrogen
____ are a series of chemicals that are used for communication between members of the same species.
pheromones
____ is an anabolic process in plants that converts carbon dioxide into glucose.
photosynthesis
____ is a molecule formed from three oxygen atoms that absorbs ultraviolet radiation from the sun.
ozone
The ____ measures how fast light travels in a vacuum, which is equal to approximately 299,492,4588 meters per second.
speed of light
____ is a metric used to measure the acidity or basicity of a substance. It is commonly said to range from 0 to 14. Values close to 0 are more acidic; values close to 14 are more basic.
pH
____ is the biological study that deals with the defining and classification of organisms.
taxonomy
____, also called leukocytes, are disease-fighting cells that are part of the immune system.
white blood cells
____ are continuous, directed flows of seawater moving horizontally and vertically throughout the world's oceans.
currents
Aside from the sun, the closest star to earth is ____, which is just over 4 light years away.
Proxima Centauri
Organic chemistry is a subdiscipline concerned with compounds containing ____, an element with atomic number 6. ____ and organic compounds form the basis of all known life.
carbon
____ is exhibited when an organism benefits at the expense of another organism.
parasitism
A ____ cell is a type of cell that possesses a nucleus, as contrasted with ____ cells.
eukaryotic, prokaryotic
A ____ is a barrier constructed to hold back water and raise its level, forming a ____ used to generate electricity or as a water supply.
dam, reservoir