An artery is composed of three layers:

• The outermost layer is termed tunica adventitia (or tunica external). It consist mainly of collagen fibres and connective tissues that anchors the arteries to other nearby tissues.

• The middle layer is named tunica media. It is made up of smooth muscles and elastic fibres that supports the artery in conveying blood at high pressures.

• The inner layer is called tunica intima (or tunica internal). It is lined by a smooth tissue called endothelium, and is made up of a fine network of connective tissues.

Please read on the layers of an artery here

All living organisms possess various features in order to survive in their environment. This is the concept of adaptation. As an instance, a fish is able to live in water because it has gills and fins.

Also, a camel is able to survive in the desert because it has large feet to aid walking on sand without sinking. It also has long eyelashes to help protect it from the blowing sand and wind.

Plants are also able to live in different habitats because they have the required adaptive features towards that habitat. For instance:

• Plants that live in/on water are termed hydrophytes.

• Plants that live on land with moderate amount of water are termed mesophytes.

• Plants that live on deserts or arid lands are termed xerophytes.

The point is:

All organisms have various features on them that enables them adapt in their habitat