Consider statements about ecology: 1. A population consists of individuals of the same species. 2. A community consists of interacting populations. 3. An ecosystem consists of biotic and abiotic components. Which are correct? MCQ with Answer and Explanation
Consider statements about ecology: 1. A population consists of individuals of the same species. 2. A community consists of interacting populations. 3. An ecosystem consists of biotic and abiotic components. Which are correct?
A. 1 and 2 only
B. 2 and 3 only
C. 1, 2 and 3
D. 1 and 3 only
Answer: Option C
Solution (By JKSSB Mock Tests)
A population is a group of individuals of the same species living in a specific geographic area and capable of interbreeding. A community comprises all the interacting populations of different species (plants, animals, microbes) living together in a defined area. An ecosystem is a functional unit of nature that encompasses both the biotic (living community) and abiotic (non-living physical environment like soil, water, sunlight) components, interacting as a complex system. All statements are correct.
Explanation:
Trypsinogen, secreted by the pancreas, is activated to trypsin by enterokinase (intestinal enzyme). Trypsin then activates other zymogens. Pepsin is active in the stomach, rennin in infants, amylase digests starch. This cascade prevents premature protein digestion in the pancreas.
Explanation:
Light reactions occur in the thylakoid membranes, converting light energy into chemical energy in the form of ATP and NADPH, with oxygen as a by-product. These energy-rich molecules are used in the Calvin cycle (light-independent reactions) to fix COâ‚‚ into carbohydrates. Glucose is a final product of the Calvin cycle. Oxygen is released but not the primary product. Thus ATP and NADPH are the main outputs.
Explanation:
Phloem is composed of sieve tube elements, companion cells, phloem parenchyma, and phloem fibers. Sieve tubes are living cells that transport organic solutes; companion cells assist in loading and unloading. Tracheids and vessels are xylem elements. Fibers and sclereids are sclerenchyma cells. Guard cells regulate stomatal movement.
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