An organism that obtains energy and nutrients by feeding on other organisms or their remains. A food web is a model of the feeding relationships between many different consumers and producers in an ecosystem. Without plants (the primary producers) consumers and decomposers would not be able to live. Producers always start every food chain. A consumer, also called a heterotroph, is an organism that cannot make its own food. It must eat producers or other organisms for energy.
- Bicycling on the road - voluntary action
- Beating of the heart - involuntary but non-reflexive action
- Jumping when startled by a loud horn - reflexive action
- Blinking your eyes every few seconds - reflexive action controlled by the brain
Reflexive actions are the simple and fundamental movements. Those are automatic muscle responses to particular stimuli. Examples: removing the arm when it burns, moving the feet when it step tt a sharp object etc.
Voluntary actions are under the control of the brain which “orders” and sends information to motor cortex to perform the movement. Examples: arm and leg moving, doing any sport etc.
Involuntary actions are made without the intermediation of the brain. Examples: crying, blinking, breathing, heart beating etc.
DNA helicase untwists the helix at the replication origins. Then the DNA is seperated into a "Y" shape called the replication fork.