Answer:
They all build up a DNA strand.
Explanation:
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Answer: 2: b. fusion of male and female gametes to make a zygote
Explanation: Sexual reproduction can be defined as the mode of reproduction in which the haploid male and female gamete cells fuse to form a diploid zygote cell by the process of fertilization.
Answer 3: c. none of the above
Explanation: The asexual mode of reproduction is used by the simple organisms to produce their offsprings. In this method only a single parent is involved. It does not involve the formation of gametes like in sexual reproduction and no fertilization takes hence, no zygote formation takes place.
Answer:
Ozone is formed in the stratosphere naturally.
High energy solar radiation strike the oxygen atoms O2, the two atoms split apart. The freed atom collides with another oxygen atom O2 forming O3 (Ozone)
Ozone layer is destroyed when chloroflourocarbons and halons.
CFCs and halons cause chemical reactions that break down ozone molecules. Consequences ofnozone depletion are that UV radiations are not filtered and they reach the earth causing damage to eyes and skin.
Explanation:
Ozone layer is a protective layer which protects from UV damaging radiations. It is formed when oxygen atoms are broken down by photolysis and a freed oxygen atom combines with another amd form O3.
Ozone is being depleted now because chlorofluorocarbons (CFCs) and halons—gases found in aerosol spray cans and refrigerants—are released into the atmosphere they decrease the ozone's ultraviolet radiation-absorbing capacity.Ozone layer depletion causes increased UV radiation levels at the Earth's surface, which is damaging to human health. Negative effects include skin cancers, eye cataracts and immune deficiency disorders.
Segments of dna capable of moving from one area in the dna to another are called: transposable elements or "transposons."
