<span>Molecular clock is a scale which uses a technique whereby evolutionary time for different life forms is deduced from the mutation rate of biomolecules. Biomolecular data used for calculations in order to come up with the prehistoric time scale normally uses nucleotide sequences for DNA or amino acid sequences for proteins.
Hence, in order to develop a molecular clock, one would need: a sequence of molecules, the rate at which changes occur in a type of molecule and how much total change has occurred in a type of molecule from different species.</span>
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.
<h2>Answer</h2>
- Wind
- Sunlight
- Plants
- Soil
- Coal
- Minerals
- Water
- Animals
In short it's natural resources.
Answer:
Catalase is an enzyme in the liver that breaks down harmful hydrogen peroxide into oxygen and water. When this reaction occurs, oxygen gas bubbles escape and create foam.
