Answer:
The Cell.
Explanation:
Living organisms are composed of single or multiple cells. The cell is termed the building block of life. Single cell organisms are called unicellular while multiple cell organisms are called multicellular. A single cell organism is capable of performing all the basic functions of life like reproduction, respiration etc
decreased ability to survive changing conditions
Hope this helps
Receptors detect changes in the environment. For a stimulus to elicit a response, certain cells must have an appropriate receptor. Stimulation of the receptor initiates a specific signal pathway.
<span>A. endoskeleton
</span>Endoskeleton is not a characteristic of Arthropods that has attributed to their diversity and success. Endoskeleton is defined as inner characteristics of the skeletal feature of an organisms such as bears, humans, fish and etc.
Exoskeleton on the other hand is the trait by which arthropods posses. It is skeletal feature that is described outside or is extrinsic, this is evident as crabs have their skeletons outside of their body.
