Which of the following is an example of a unicellular organism?
A. Hydra
B. Earthworm
C. Mushroom
D. Paramecium
Answer: Option D
Solution (By JKSSB Mock Tests)
Paramecium is a unicellular ciliated protozoan found in freshwater. Earthworm and Hydra are multicellular animals, mushroom is a multicellular fungus. Unicellular organisms carry out all life processes within a single cell.
Consider statements about environment: 1. The greenhouse effect is entirely unnatural. 2. Deforestation contributes to global warming. 3. Ozone depletion causes skin cancer. Which are correct?
Explanation:
The greenhouse effect is a natural process that keeps Earth warm; the problem is the enhanced greenhouse effect due to human activities. Deforestation reduces the number of trees absorbing CO2, increasing atmospheric greenhouse gases and contributing to global warming. Ozone layer depletion allows more harmful UV-B radiation to reach Earth, significantly increasing the risk of skin cancers. Thus, statements 2 and 3 are correct.
Explanation:
Simple columnar epithelium lines the stomach, intestines, and gallbladder, and functions in secretion and absorption. It often has microvilli (brush border) or goblet cells. Squamous epithelium lines alveoli and blood vessels, cuboidal kidney tubules.
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