The investigators could distinguish human hair from animal hair by the patter of pigmentation and by the medullary index.
The pigmentation in human hairs is denser toward the cuticle, whereas in animal hair is denser toward the medulla. Human hairs are usually one colour throughout the whole length, while animal hairs may change colour suddenly.
The medulla in humans is thinner than in animals: the medullary index for human hairs is 0.33 or less; the medullary index for animal hairs is 0.5 or more.
Answer:
Part A: The process of sexual reproduction is important because by this process organisms with varied genetic characteristics can be formed. Crossing over and independent assortment allow individuals to be born which are not alike to another and their parents. As a result, genetic diversity is produced.
Part B:
The process 1 is meiosis. The process 3 is development by mitosis.
The reproductive organs form sperm and egg by the process of meiosis. During this process, the number of chromosomes is reduced so that the number of chromosomes of an individual can be maintained.
The zygote converts into an embryo in a process called germinal development. The zygote replicates by mitosis to form into an embryo.
Answer:
Letter E - exons are cut from the strand and removed
Explanation:
Letter A and B are incorrect because the poly-A tail and guanine cap are added to the 3’ and 5’ end respectively. They aid in translation of the mRNA, while serving as protection. The poly-A tail is repeated adenine nucleotides, while the guanine cap is a modified guanine nucleotide.
Letter C is incorrect because alternative splicing is one mechanism for generating variation, and is thought to be one of the reasons for why humans have smaller genomes than other organisms and still maintain high complexity. Alternative splicing is incredibly important because it produces more than one transcript from a pre-mRNA.
Letter D is incorrect because introns are the non coding portions of the mRNA. They are excised to make a smaller mRNA transcript, and one that contains all the protein genes.
This letter E is the correct answer, because exons are the coding portions of the mRNA, and are not excised during RNA processing.
Hope that helped! If I made a mistake, please let me know.
C...the key is that they are photosynthetic...so they produce oxygen (like plants)!