The answer is A.) Layers
hope it helps.
Metabolism is a set of chemical reactions happening within an organism. These reactions are necessary to maintain the living state of cells, allowing them to reproduce, grow, and respond to environment.
Answer:
Number of bacteria required 
Explanation:
Given -
Size of each bacterium
micrometers long
These bacteria are arranged end to end.
The size of chain to be formed is equal to
centimetres
Let us say that in forming a chain of
centimetres nearly X number of individual bacterium are required.
hence, number of bacterium required to form
centimetres chain can be represented as

Number of bacteria required 
Answer:
Access. A basic feature of any greenhouse is access. ...
Vents. One of the first greenhouse features necessary is a means of controlling the climate – most importantly, venting excess heat. ...
Fans. Fans inside a greenhouse are necessary for two basic functions. ...
Rollup Sides. ...
Heaters. ...
Shelves and Benches. ...
Water. ...
Electricity.
Explanation:
theres more but these are the important ones .
The term for a lack of a nutrient is called malnutrition.
You can tell because the prefix mal- derives from French, meaning bad, or wrong.
Therefore, it literally means "bad-nutrition", meaning you're not getting enough nutrition. In other words - a lack of nutrition.