T3 and T4 also known as triiodothyronine and thyroxine
Answer: The immune system
Explanation:
The immune system is a complex network of proteins and cells that defends the body against infection or any invasion. The human defense system in the body is actually made up of entire organs and vessel systems like the lymph vessels. The immune system is made up of organs that control the production and maturation of certain defense cells.
Initially, all living things are subjected to attack from disease causing agents. Even bacteria, so small that more than a million could fit on the head of a pin, have systems to defend against infection by viruses. This kind of protection gets more sophisticated as organisms become more complex.
Answer:
perform functions that tissues cannot carry out on their own
Explanation:
In the hierarchy of living system organs come after tissues and before organ systems. Hence, organs are complex then tissues and perform functions that tissues wont be able to perform on their own.
A organ is made up of various types of tissues. They can be divided into two categories, main tissue and sporadic tissue. Main tissue or parenchyma is unique to that organ and defines the function of the organ. For example: Cortex and medulla together form the main functional tissue in kidney. Similarly, myocardium is the main tissue of the heart. Sporadic tissue has blood vessels, nerves and connective tissues.
Answer:
coral is not a rock or a plant it is an animal
Explanation:
a single coral is made up of many tiny creatures that are called polyps, together they make up a coral.
