These are the smallest units of life that make up all living things.
Cells
This organelle produces energy for the cell.
Mitochondrion
The correct order from smallest to largest: cell, ___, organ, system.
Tissue
This body system is most directly affected by heart disease.
Circulatory System
The skin helps maintain homeostasis by doing this.
Regulating body temperature
This type of organism is made of only one cell.
Amoeba
Plant cells use this organelle to make glucose using sunlight.
Chloroplast
A group of similar cells working together forms this level of organization.
Tissue
This system is threatened when bacteria infect the lungs.
Respiratory System
When you touch something hot, these receptors send messages to the brain.
This cell structure controls what enters and leaves the cell.
Cell Membrane
This structure provides support and protection and is found in plant cells but not animal cells.
Cell Wall
The stomach and intestines working together are an example of this.
Organ System
This system includes the brain, spinal cord, and nerves.
Nervous System
This body function is most affected when nerve cells are damaged.
Sensing and responding to stimuli
This organelle contains instructions that determine traits passed from parents to offspring.
Nucleus
This jelly-like substance fills the cell and holds organelles in place.
Cytoplasm
This level of organization is capable of carrying out all life processes.
Organism
This system breaks down food so nutrients can be absorbed by the body.
Digestive System
During exercise, muscles need more of this gas.
Oxygen
These structures inside cells perform specific jobs, similar to machines in a factory.
Organelles
Muscle cells contain many of this organelle because they need large amounts of energy.
Mitochondria
If tissues cannot work together properly, this higher level will not function correctly.
Organ System
Oxygen is transported throughout the body mainly by this system.
Circulatory System
This system works with the nervous system to help the body react quickly to changes.
Muscular system