cells
This thin, flexible outer layer surrounds all cells and controls which substances, like water and nutrients, can enter or leave.
What is the cell membrane?
In the "levels of organization" hierarchy, this level sits right between cells and organs.
What is tissue?
This level of organization is defined as a structure made of two or more different types of tissues working together to do a complex job.
What is an organ?)
This system, which includes the heart and blood vessels, acts like a delivery truck, carrying oxygen and nutrients to every cell in your body.
What is the circulatory system?
This level is defined as a single, complete living thing that can perform all the basic functions of life on its own.
What is an organism?
Found only in plants, this green organelle captures energy from sunlight to make food.
What is photosynthesis
This type of tissue is made of fibers that can contract and relax, allowing your body to move or your heart to beat.
What is muscle tissue?
This vital organ, made primarily of nervous tissue, acts as the "boss" of the body, processing information and sending out instructions.
What is the brain?
Made up of the mouth, stomach, and intestines, this system breaks down the food you eat into tiny molecules the body can use for energy.
What is the digestive system?
While humans are made of trillions of cells, these simple organisms, like bacteria or amoebas, consist of only one single cell.
What is a unicellular organism?
While animal cells have many small ones, plant cells have one large "central" version of this organelle to store water and provide support.
What is a vacuole?
This tissue type acts like a high-speed internet cable, carrying electrical signals between your brain and the rest of your body.
What is nerve tissue?
In the human body, these two organs are filled with spongy tissue that allows you to take in oxygen and get rid of carbon dioxide.
What are the lungs?
This system is made of 206 bones that provide shape to your body, protect your internal organs, and even make blood cells.
What is the skeletal system?
Animals, plants, and fungi are this type of organism, meaning they are made of many specialized cells working together.
What is a multicellular organism?
These tiny, grain-like structures are responsible for making proteins for the cell, often found floating in the cytoplasm or attached to the E.R.
What are ribosomes?
Bone, cartilage, and even your blood are all classified as this type of tissue because they support and hold parts of the body together.
What is connective tissue?
This J-shaped organ uses muscular tissue to churn food and epithelial tissue to secrete acid for digestion.
What is the stomach?
Consisting of the brain, spinal cord, and nerves, this system sends high-speed electrical signals to tell your body how to react to the world.
What is the nervous system?
To be considered a living organism, a thing must be able to do these three "R" words: Respond to the environment, Reproduce, and this... which means getting bigger.
What is Grow?
This scientific theory has three parts: all living things have cells, cells are the basic unit of life, and all cells must come from these.
What are pre-existing cells?
This tissue type, called epithelial, forms the outer layer of your skin and lines the inside of your organs like a protective wallpaper.
What is epithelial tissue?
While humans have hearts and lungs, plants have these organs that stay underground to absorb water and minerals from the soil.
What are roots?
This system’s main job is to bring oxygen into the body through the lungs and exhale carbon dioxide as waste.
What is the respiratory system?
All organ systems in a complex organism must work together to maintain this stable internal environment, even when the outside world changes.
What is homeostasis?