Organs only exist in animals are less complex than the tissues which make them perform functions that tissues cannot carry out on their own are made of only one type of tissue

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.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .