The answer is external stimulus
Prokaryotic bacteria are surrounded by a cell membrane that contains the transport proteins to regulate the entry and exit of materials through the cell, the cell wall to help maintain cell shape and structure, and the capsule, which aids against drying out and protects bacteria from a host's immune system.
<h3><u>Explanation:</u></h3>
Bacteria are the prokaryotic organisms that are found in every part of Earth. These organisms do have an interesting ultrastructure. The coverings of the bacteria are three in layer. They are
A. The outer capsule.
B. The middle cell wall.
C. The inner cell membrane.
The capsule is the outermost covering of bacteria that is formed of different slimy materials. These materials contains hygroscopic substances which can absorb water from the surroundings even when the water concentration in outside is very very low. This layer of protection outside bacteria help them to protect themselves against drying out at dry conditions.
The middle cell wall is formed of polymers of N acetyl glucosamine and N acetyl muramic acid. This layer is chitin in nature and is strong enough to maintain the shape and size of bacteria irrespective of outer conditions.
The innermost layer of bacteria is cell membrane which is formed of proteins and lipids bilayer and this cell membrane contains different transport for proteins which help in transport of different substances like water and nutrients inside the cell by means of active transport or passive diffusion.
It is Convergent evolution
The answer would be the ozone layer. <span>A layer of ozone in the upper atmosphere absorbs </span>UV radiation<span> and </span>prevents<span> most of it from </span>reaching<span> the </span>Earth<span>. ... This means that more </span>ultraviolet radiation<span> can pass through the atmosphere to the </span>Earth's<span> surface, particularly at the poles and nearby regions during </span>certain<span> times of the year.
I hope that this helped you! Good luck. :)</span>
