Marine debris is defined as any man-made solid material that goes into waterways either directly or indirectly. Eighty percent of the marine debris comes from the land-based sources. Examples of marine debris are soda cans, plastic bag, cigarette waste. Anything that ends up in a water body that has a potential in harming the marine life is a marine debris.
Answer:e. multiple of the options are true
Explanation:
DNA central dogman involves DNA replication, DNA transcription and DNA translation which involves the formation of protein.
Replicated DNA are transcribed to an intermediary mRNA(Messenger ribonucleic acid) from where it is moved from the nucleus to ribosome in the cytoplasm. Enzyme RNA polymerase helps in proof reading ,replication and transcription of bases during transcription. translation takes place in the ribosome with the help of ribosome in the presence of enzyme tRNA (transferase ribonucleic acid) that reads the codon and brings corresponding amino acid which are functional protein.
Answer: C. Homologous chromosomes are separated in meiosis but not in mitosis.
Explanation: There are two main types of division that take place in eukaryotic cells, mitosis, and meiosis. Mitosis is the type of division that is used for growth, repair, and replacement of tissues. Therefore it is not necessary that the cells have different chromosome numbers or are varied genetically in the daughter cells in the case of mitosis.
Meiosis is the division that takes place to form the gametes for sexual reproduction. It is important in the first stages of meiosis I, to introduce variation and to halve the chromosome number.
Chromosomes numbers are halved (from 46 to 23) during meiosis I because the gametes (sperm and egg) come together and fuse during fertilization to form a zygote. When this fusion occurs (23 from the zygote and 23 from the egg), the chromosome number needs to be returned to that of the parent cell (46).
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Genetic variation is introduced during synapsis which only occurs in meiosis, not mitosis. Homologs exchange genetic information during crossing over of synapsis. Entire chromosomes also separate during meiosis I.
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At the end of meiosis, four genetically unique cells are produced with half the number of chromosomes as the parent cell (23 cromosomes) . After the process of mitosis is completed, two cells genetically identical to each pther are produced and have the same number of chromosomes as the parent cell (46 cromosomes).
Genetic variation is actually important because of changing environmental conditions.
The person who studies living things is called a biologist
