The concept of the struggle for existence<span> concerns the competition or battle for resources needed to live. It can refer to human society, or to organisms in nature. The concept is ancient, and the term </span>struggle for existence<span> was in use by the end of the 18th century. From the 17th century onwards the concept was associated with a population exceeding resources.
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Answer:
Parenchyma has a thin cell wall of their cells, and are made up of cellulose. Whereas collenchyma cells have an uneven cell wall made up of pectin and hemicellulose. There is a hard and thick cell wall present of the sclerenchyma cells, which is made up of the lignin.
Explanation:
Answer:
In the cardinals, if the females start using a different criterion than the color of the feather when they choose couple, most likely to happen is that decreased variation in the shades of red because no form of the trait is advantageous.
Explanation:
Options for this question are:
- <em>Increased variation in the shades of red because the selection pressure has been relieved.</em>
- <em>Increased variation in the shades of red because the cardinals try different ways to impress the females.</em>
- <em>Decreased variation in the shades of red because no form of the trait is advantageous.</em>
- <em>Decreased variation in the shades of red because the only reason for variation was selection pressure.</em>
In the context of natural selection, male cardinals court females using the coloring of their feathers as a form of sexual selection. This means that the shades of red in the feathers are a selection criterion in these birds, and the more visible shades represent an advantage.
But, if the selection criterion was not the color of the feathers, this trait would no longer represent an advantage in the competition between the males to be chosen as a mate. Instead, the trait that would determine sexual selection would be the one that experiences an increase in its variation<em>.</em>
Answer: warm water
El Nino is a climate change pattern which describes the unusual warming of water of Pacific Ocean. The atmospheric pressure above the water decreases. The warm water increases the temperature of wind. The warm wind moves towards the East Equator.
