Answer:
<em>The correct option is D) How is the number of frogs in Massachusetts affected by pollution</em>
Explanation:
A scientific question can be described as a question which can be answered through the scientific method of research. Based on the scientific question, a hypothesis can be formulated. For example, for the option D, the hypothesis can be 'if the pollution increases, then the number of frogs decreases.' A hypothesis is a tentative statement which can be tested through experiments. Based on these experiments, results are formulated and conclusions are drawn. The question mentioned in option D can be answered through this method hence, it is the correct option.
Answer:
Option C
Explanation:
Dr. Leland Hartwell used baker’s yeast, <em>Saccharomyces cerevisiae</em>, as a model system, which was a highly suitable model for cell cycle studies. He introduced the concept of Checkpoints where he said cells are arrested if damaged so that the cells repair system can work to correct such damages. Dr. Paul Nurse used a different type of yeast, <em>Schizosaccharomyces pombe</em>, a type of yeast distantly related to the baker's yeast as a model organism.
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<h3>⇝ <u>Epidermis</u> :</h3>
Protective tissues includes epidermis & cork. Epidermis is basically a simple permanent tissue, protective in function. It forms one-cell-thick covering over all the parts of plant.
<h3>⇝ <u>Characteristics of Epidermis</u> : </h3>
- Epidermis is formed of living cells, arranged in a single layer.
- In aerial parts, epidermis is covered with a waterproof and noncellular waxy covering called cuticle.
- Cells form a continuous layer, but in leaves epidermis has small openings called stomata.
- Each stoma is guarded by a pair of bean-shaped guard cells which govern opening & closing of stomatal aperture.
<h3>⇝ <u>Functions of Epidermis</u> :</h3>
- Epidermis protects the underlying tissues from mechanical injury, chemicals & infection.
- Cuticle of epidermis protects against water loss & desiccation. It checks the rate of transpiration & evaporation and prevents wilting.
- Stomata in the epidermis of leaves help in gaseous exchange during respiration & photosynthesis.
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