Test : Plant Life - 3 Class 5 Science MCQs & solutions - Free

Cotyledons are commonly known as seed leaves. They are the first leaves that appear when a seed germinates.

Key points about cotyledons:

• They provide nutrients to the young plant until true leaves develop.
• Each seed can have one or more cotyledons, depending on the plant species.
• Cotyledons can vary greatly in shape and size.

Understanding cotyledons is essential in botany, as they play a crucial role in the early growth of plants.

The best soil for growing cotton is Black Soil (Option A). Here's why:

• Black soil holds water and has lots of nutrients.
• Because it doesn’t dry out too quickly and feeds the plant well, cotton grows strong in black soil.

Here’s why B, C and D aren’t the best choice for cotton:

B: Loam

• Loam is a good all-round soil (mix of sand, silt and clay) and works for many crops.
• But cotton needs extra moisture retention and higher natural nutrient levels than loam alone provides.

C: Sandy

• Sandy soil lets water pass through very quickly, so it can’t hold enough moisture for cotton’s long growing season.
• It’s also low in the nutrients cotton plants need to make strong fibers.

D: Clay

• Clay soil holds too much water and can become waterlogged, which can drown cotton roots.
• It’s hard for young cotton shoots to push through heavy clay.

Only black soil has the right balance of nutrients and moisture-holding ability that cotton plants love.

Sugarcane reproduces by stem cutting. Sugarcane is a perennial grass that reproduces asexually through stem cuttings. This means that new plants can be grown from sections of the stem. Here is a detailed explanation of how sugarcane reproduces through stem cutting:

1. Selection of the stem

• A healthy and mature sugarcane plant is selected for stem cutting.
• The stem should be free from any disease or damage.

2. Preparation of the stem

• The stem is cut into sections, typically around 2-3 feet long.
• Each section should have at least one bud or node present.

3. Planting the stem

• The cut sections of the stem are then planted in the soil.
• They are usually planted horizontally or at a slight angle to encourage better root development.

4. Root and shoot formation

• The planted stem sections start developing roots from the nodes.
• Simultaneously, shoots emerge from the buds present on the stem.

5. Growth and development

• As the roots and shoots grow, a new sugarcane plant is formed.
• The shoots develop into new stalks, while the roots provide the necessary nutrients and water for growth.

6. Harvesting

• Sugarcane plants grown from stem cuttings take several months to reach maturity.
• Once the stalks have reached the desired size and sugar content, they are harvested for processing into sugar or other sugarcane products.

In conclusion, sugarcane reproduces through stem cuttings, where sections of the stem are planted in the soil, leading to the development of new plants with root and shoot growth.

• In mushrooms, new plants can grow from spores.
• Spores are tiny reproductive units that can develop into new fungi under the right conditions.
• Other parts like stems, roots, or leaves do not typically reproduce new plants in mushrooms.

• Farmers should use insecticides to protect their crops from insects.
• However, it's important to be cautious with their use, as overusing insecticides can be harmful to both soil quality and human health.

• Identifying the Plant with an Underground Stem

  Among the options given, the plant that has an underground stem is Ginger (Option B).

  Ginger is a rhizome, which means its stem grows horizontally underground.

  The ginger plant stores nutrients and produces shoots and roots from its underground stem.

• Eliminating Other Options

  • Sugarcane (Option A) does not have an underground stem. It has a tall, upright stem known as a culm.
  • Hibiscus (Option C) does not have an underground stem. It has an upright stem that grows above the ground.
  • Rose (Option D) does not have an underground stem. It has a woody stem that grows above the ground.

• Conclusion

  The correct answer is Ginger (Option B) as it is the only plant among the options given that has an underground stem or rhizome.

Plants that can be grown from the roots of a plant

• Potato: Potatoes are not grown from the roots of a plant. They are grown from the tubers of the potato plant.
• Ginger: Ginger is grown from the rhizomes of the ginger plant, which are underground stems, not roots.
• Sweet potato: Sweet potatoes can be grown from the roots of a plant. When a sweet potato is planted, new roots will develop, and new sweet potatoes will grow from these roots.
• Sugarcane: Sugarcane is not grown from the roots of a plant. It is grown from stem cuttings or pieces of the stalks.

Therefore, the correct answer is option C: Sweet potato.

The correct answer is B: (i - C), (ii - A), (iii - D), (iv - B).

Explanation of Pairings

• (i - C):Dispersal of seed → Scattering of seed
  Dispersal means seeds get carried away from the parent plant.
  Wind, water, animals or people can scatter (“disperse”) the seeds so new plants can grow in different places.
• (ii - A): Germination → Growth of a seed
  Germination is when a seed “wakes up” and begins to grow.
  You’ll see a tiny root push down into the soil and a shoot grow up toward the light.
• (iii - D): Cotyledon → Part of a seed
  A cotyledon is one of the seed’s first leaves.
  It stores food for the baby plant until its true leaves can make food by photosynthesis.
• (iv - B): Manure → Dead and decaying matter
  Manure is made from animal dung or rotting plants.
  This dead, decaying material is full of nutrients that help the soil stay rich and plants grow strong.

The correct answer is C: Winter. Crops grown in the winter season are known as rabi crops. Rabi crops are typically sown in October and November and harvested in April and May. These crops require cool temperatures and a sufficient amount of water for their growth. Some examples of rabi crops include wheat, barley, mustard, gram, and peas.

Explanation of Options

• A: Summer: Summer crops are known as kharif crops, not rabi crops.
• B: Autumn: Autumn is not a specific season for crop cultivation. It is a transition period between summer and winter.
• C: Winter: Correct answer. Crops grown in the winter season are known as rabi crops.
• D: Spring: Spring crops are also known as zaid crops, not rabi crops.

To summarise, rabi crops are grown in the winter season and include crops like wheat, barley, mustard, gram, and peas.

Carrot, radish, and turnip are all root vegetables, meaning they grow from the root part of the plant and cannot be propagated from the stem. Potato, on the other hand, is a stem tuber. It can be cut into pieces, each containing an 'eye' (bud), and planted to grow new potato plants. Thus, only potato can be grown from the stem among the given options.

• Fencing is a method that involves enclosing fields to protect crops from animals.
• This approach prevents grazing animals, such as goats, cows, and buffaloes, from reaching the crops.
• By using fences, farmers can effectively safeguard their harvests from damage caused by these animals.

The eyes of a potato are actually buds. They are small, dormant shoots found on the surface of the potato. These buds can grow into new potato plants when conditions are right. Here are some key points:

• Potato eyes are not roots or leaves.
• Each eye can potentially develop into a new plant.
• They are essential for planting and propagation.

• Organic fertilizers are made from natural materials like decaying plants, animal dung, and other organic matter.
• They provide essential nutrients to the soil, improving its quality and supporting plant growth in an eco-friendly way.

• Fertilization is the process of adding nutrients to the soil, enriching it to promote the growth of crops.
• This can be achieved through the use of organic or inorganic fertilizers.

• Kharif crops are sown in summer, as soon as the monsoon rains begin (around June–July).
• They grow through the rainy (monsoon) season and are harvested in September–October.
• Because their growth period spans both summer (pre-monsoon) and the monsoon, the best choice is “Summer and Monsoon.”

Why the other options don’t fit

• A: Winter → Winter crops are called rabi crops, not kharif.
• B: Spring → Spring (zaid) crops are a small, short season between rabi and kharif.
• C: Monsoon → Kharif growth happens during the monsoon, but seeds are actually sown in summer just before the rains.

Only “Summer and Monsoon” covers the full kharif season.