Tag: evs

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

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

  1. Ceratophyllum

  2. Najas

  3. Trapa

  4. Utricularia
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ceratophyllum (hornwort) is a free-floating hydrophyte with roots that anchor in mud at the bottom while leaves float on or near the water surface. Najas is completely submerged, Trapa (water chestnut) has floating leaves but different growth form, and Utricularia (bladderwort) is also typically submerged or free-floating. The key distinction is Ceratophyllum's mud-anchored roots with floating foliage.

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

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

  1. Hydrophytes

  2. Xerophytes

  3. Mesophytes

  4. Epiphytes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrophytes (water-dwelling plants) show reduction in vascular tissue (xylem and phloem) because water provides direct support and nutrient availability, reducing need for extensive transport. Mechanical tissue is reduced since water buoyancy provides support. Cuticle is thin or absent because water loss is not a concern - in fact, these plants need to absorb water directly through surfaces. These are key adaptations to aquatic environment.

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


Animals which live on the floor of sea are called benthic

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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'.
Multiple choice evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

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.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  1. aphotic

  2. photic

  3. euphotic

  4. nonphotic
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The photic zone is the depth in an aquatic ecosystem where sunlight penetrates and photosynthesis is possible. Aphotic zones receive no light, euphotic is a specific subtype of photic zone, and 'nonphotic' is not standard terminology.

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

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.

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.
Multiple choice evs life in water aquatic plant adaptations pollination through water aquatic adaptation extreme adaptations

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

  1. Aquatic ecosystem

  2. Grassland ecosystem

  3. Forest ecosystem

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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. 

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

Standing water 'ecosystem' is known as

  1. Running water ecosystem

  2. Lentic aquatic ecosystem

  3. Lotic ecosystem

  4. Lakes ecosystem
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lentic ecosystems are standing water bodies like lakes and ponds with minimal flow. Lotic refers to running water ecosystems (streams, rivers). 'Running water ecosystem' is a description, not a formal term. 'Lakes ecosystem' is too specific - lentic includes ponds too.