Tag: evs

Questions Related to evs

Plants growing on damp (shady) places are ______________.

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. Hydrophytes

  2. Hygrophytes

  3. Mesophytes

  4. Phreatophytes

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Correct Option: A

Which one of the following hydrophytes has its roots fixed in mud and leaves floating on water?

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. Ceratophyllum

  2. Najas

  3. Trapa

  4. Utricularia

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Correct Option: A

Reduction in vascular tissue, mechanical tissue and cuticle is characteristic of :

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. Hydrophytes

  2. Xerophytes

  3. Mesophytes

  4. Epiphytes

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Correct Option: A


Animals which live on the floor of sea are called benthic

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. True

  2. False

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Correct Option: A
Explanation:
  • Benthic animals(benthos), refer to organisms who live at the lowest level(floor) of a water body(ocean or a lake or sea), sometimes even permanently attached to the bottom. For example, polychaete worms, bivalves, echinoderms, sea anemones, corals, sponges, sea squirts, turbellarians and larger crustaceans such as crabs, lobsters, etc.
  • Hence Animals which live on the floor of the sea are called benthic is a true statement.
  • So, the correct answer is 'True'.

State whether the following statements are true or false.
Streamlined body of fish is suited for active locomotion in water because it offers little or no resistance in swimming.

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. True

  2. False

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Correct Option: A
Explanation:

The body of the fish is supported by endoskeleton made up of bones. Fish possess a streamlined body which helps them to swim in water. Fish swim with the help of their fins. Streamlined body helps in orientation of the fish movement in a particular path.

So the given statement is true.

Consider the following plants.
a. Isoeles
b. Marsilea
c. Sagittaria
d. Salvinia
Which of the above are hydrophytes?

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. $1$ and $2$

  2. $2, 3$ and $4$

  3. $1$ and $3$

  4. $1, 2, 3$ and $4$

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Correct Option: A

In an aquatic ecosystem, the depth to which light penetrates is called

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. aphotic

  2. photic

  3. euphotic

  4. nonphotic

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Correct Option: B

Two species of Amoeba X & Y were kept in fresh water & got adapted. Species developed contractile vacuole. When both were transferred to sea water and got adapted, both X and Y lost their contractile vacuole. From these observation were concluded that.

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. Both X & Y are marine species

  2. Species Y is marine & X is fresh water

  3. Species X is marine & Y is fresh water

  4. Both X & Y are fresh water species

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Correct Option: A
Explanation:
The contractile vacuole eliminates excess water which enters the cell by osmosis. Because of the hypotonic nature fresh water continuously transfers into amoeba by osmosis. To avoid this, they develop contractile vacuoles. Marine amoeba is isotonic in water and they do not have contractile vacuoles. Both X and Y species are marine species. That’s why they developed contractile vacuoles when they kept in freshwater. But they lost their contractile vacuoles when transferred to seawater. There is already hypertonic environment in seawater to control water loss by themselves. 

Hence, the correct answer is option A.

Phosphorous usually becomes a limiting factor at certain times of the year in which ecosystem? 

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. Aquatic ecosystem

  2. Grassland ecosystem

  3. Forest ecosystem

  4. All of the above

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Correct Option: A
Explanation:

Generally, phosphorus is the limiting nutrient in freshwater aquatic systems. That is, if all phosphorus is used, plant growth will cease, no matter how much nitrogen is available. Phosphorus functions as the growth-limiting factor because it is usually present in very low concentrations. The natural scarcity of phosphorus can be explained by its attraction to organic matter and soil particles. Any unattached or free phosphorus is quickly removed from the aquatic system by algae and larger aquatic plants. Excessive concentrations of phosphoruscan quickly cause extensive growth of aquatic plants and algal blooms. Several detrimental consequences may result. Excessive algae and plant growth can lead to depletion of the oxygen, that is dissolved in the water. 

Standing water 'ecosystem' is known as

evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

  1. Running water ecosystem

  2. Lentic aquatic ecosystem

  3. Lotic ecosystem

  4. Lakes ecosystem

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Correct Option: B