Answer:
The pH of the soil, which is a measure of the acidity of the soil, governs to a large extent what is suited to and will grow well on a particular soil. Thus, agricultural crops, many of which go on to become our food, require soils in a particular pH range in order to produce their best yields. Both garden and wild flowers have a pH range in which they grow best. Similarly most organisms that live in the soil will operate in soils in a pH range that suits them. For example, one of the most common species of earthworms,has a strong preference for soils with a pH above 5.5 to just over 7.0. Other species of earthworm such as Allolobophora longa can tolerate pHs less than 5.5 but only down to about 4.5. Below pH 4.5 in Western Europe at least, there are usually few earthworms in the soil. pH also has an important effect on the availability of plant nutrients. Several nutrients become less available at the lower end of the pH range, i.e. below pH 5.5 and the availability of a few tails off significantly at pHs above 7.5. It is important that those who use the soil for purposes that depend on soil nutrients should be aware of the best pH range for key nutrients.
Explanation:
Answer:
Renewable: Water, Trees, Wind, Ice Cubes, Sunlight, Salt Water, Lumber, Paper
Non-renewable: Coal, Oil, Plastics, Bauxite (Aluminum), Natural Gas, Gold Jewelry, Iron, Soda Can
Answer:
The correct answer is (b): Individuals with certain advantageous traits are selected, in the sense that they produce the most offspring.
Explanation:
Natural selection can cause a change in allele frequencies over time, making the best alleles, those better adapted, more common in the population over generations.
This is called Fitness, and it refers to how many offspring organisms of a particular genotype or phenotype leave in the next generation, relative to others in the group.
Natural selection can act on different alleles of a single gene, or on polygenic traits.
Natural selection can shift phenotype distributions in three ways:
-Stabilizing selection: Intermediate phenotypes are more fit than
extreme ones, e.g. camouflage.
-Directional selection: One extreme phenotype is more fit than all the
others, e.g. are more hidden in shadow and survive better than other
types.
-Disruptive selection: Both extreme phenotypes are more fit than those
in the middle, e.g. mimesis on octopuses.
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