Answer:
The correct answer is "secondary succession, an ecological succession step where an area previously occupied by living beings is disrupted".
Explanation:
In ecological succession, an ecosystem changes and develops through a series of steps. The first step, is the primary successional stage where rocks or other sedimentary structures are colonized by microorganisms. The second step, where the ecosystems changes towards a relatively-stable mature stage, occurs when an area previously occupied by living beings is disrupted. This step is named secondary succession, and the most clear example of this phenomena occurs when wildfire clears oak and hickory forests.
Explanation:
Mutations increase variation within a population.
During the process of cell division, spontaneous changes within the genome can arise. These mutations are errors occur when copies of the DNA within the cell are made; mutations may range from small changes called single nucleotide polymorphisms, to large scale deletions, and additions which span multiple genes. There are two types:
- somatic: these only occur within certain cells, and arise from environmental factors such as UV light
- hereditary: occur within germ cells of the parent and later the fertilized egg which forms a zygote; these are present within all cells of the new organism.
Further Explanation:
During reproduction other events, such as crossing over during mitosis and meiosis, mutations lead to increases in genetic variation. This variation refers to the genetic characteristics present within a species. Mutations may be either beneficial or deleterious; they are maintained within cells, as they form new traits called alleles. Beneficial mutations may confer traits that increase the fitness of a species, along with ensuring survival by conferring a protective advantage- these phenotypic differences between organisms are called adaptations.
Sequences of DNA make up genes which can have different forms called alleles. DNA, which makes up the genotype, is transcribed into mRNA and later translated into amino acids which are linked together by rRNA to form proteins which make up the phenotype of an organism.Mutations in DNA sequences affect the corresponding mRNA and thus the protein encoded.
Learn more about mutations at brainly.com/question/4602376
Learn more about DNA and RNA at brainly.com/question/2416343?source=aid8411316
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Answer:
True.
Explanation:
in the early 1900s development of Salvarsan, an arsenic-based drug to treat syphilis.
Answer:
Direct contact.
Explanation:
Since it was spread through facial tissue, physical contact is needed.
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