All questions of Biology for BPSC (Bihar) Exam

1. fruits is made up of ovary
2. seed is made up of ovule
3. wood is made up of stem
4. starch is present in leaf
so the correct answer is B.

The angle b/w line and plane =cos @

C

1. Both 1 and 2

1. This statement is correct. Warm-blooded animals have the ability to regulate their internal body temperature, allowing them to remain active in cold environments where cold-blooded animals may struggle due to their reliance on external sources of heat for temperature regulation.
2. This statement is also correct. Cold-blooded animals typically have lower metabolic rates and require much less energy to survive compared to warm-blooded animals, which need to maintain a constant internal body temperature through metabolic processes that require more energy.

Range is not a measure of central tendency at all. It is an absolute measure of Dispersion that is explained by the difference between the maximum and the minimum values in a series. Now, a comparison between the stability amongst Mean, Median and Mode depends on the nature of the distribution that you're working with. Let's say your data has a lot of outliers, in such a case mean will not serve the purpose well as a measure of CT, Median would be more appropriate. Remember that Mean is affected by extreme values while Median is not. Mode is more appropriate when you're more concerned about the frequency of occurences. For example if you wanted to know what size of shoes should a shoe seller keep more in stock compared to the other sizes.

The sum of the angles of a triangle is 180 degrees.Reason (R): The sum of the interior angles of a polygon with n sides is (n-2) times 180 degrees.

Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).

Explanation: The sum of the angles of a triangle is always 180 degrees, which is a well-known geometric fact. This is because a triangle has three sides, and the sum of the interior angles of any polygon with n sides is given by the formula (n-2) times 180 degrees. In the case of a triangle, n=3, so the sum of the interior angles is (3-2) times 180 degrees, which simplifies to 180 degrees. Therefore, Reason (R) correctly explains why Assertion (A) is true.

Photoperiodism
Photoperiodism is the term used to describe the response of plants to the timing of light and darkness. This phenomenon plays a crucial role in various plant processes such as flowering, seed germination, and dormancy.

Key Points
- Plants have evolved the ability to sense and respond to changes in the length of day and night.
- Photoperiodism helps plants to synchronize their growth and development with seasonal changes in the environment.
- There are three main categories of photoperiodism: short-day plants, long-day plants, and day-neutral plants.
- Short-day plants require a period of darkness longer than a critical length to initiate flowering, while long-day plants require a period of darkness shorter than a critical length.
- Day-neutral plants are not influenced by day length and will flower regardless of the photoperiod.
In conclusion, photoperiodism is a crucial mechanism that allows plants to adapt to changing environmental conditions and ensure optimal growth and reproduction. Understanding this phenomenon is essential for agricultural practices, as it can help in determining the most suitable planting times and optimizing crop yields.

Gymnosperms are a group of plants that produce naked seeds (seeds not enclosed in a fruit) and have well-developed vascular tissues. Gymnosperms are often considered a "fossil group" because they have ancient origins and include plants like conifers that have been around for a long time. The term "gymnosperm" means "naked seed," referring to the fact that the seeds are exposed on the surface of cone scales or other structures.

Flower: The Reproductive Part of a Plant

The metamorphosed part of the shoot that is meant for plant reproduction is the flower. Flowers are the reproductive structures of angiosperms, which are a group of plants that produce seeds enclosed within a fruit. They are the most diverse and abundant group of plants on Earth, and their flowers play a crucial role in their reproductive process.

Structure and Function of a Flower

A flower is composed of several different parts, each with its specific function in the reproductive process. These parts include:

1. Petals: Petals are the colorful, leaf-like structures that surround the reproductive organs of the flower. They are responsible for attracting pollinators, such as insects or birds, to facilitate pollination.

2. Sepals: Sepals are the small, usually green, leaf-like structures that protect the developing flower bud. They are located at the base of the flower and enclose it before it blooms.

3. Stamens: Stamens are the male reproductive organs of the flower. They consist of two main parts: the filament and the anther. The filament is a thin stalk that supports the anther, which contains pollen grains. Pollen is the male gamete that is necessary for fertilization.

4. Carpels: Carpels are the female reproductive organs of the flower. They are composed of three main parts: the stigma, style, and ovary. The stigma is the sticky structure at the top of the carpel that receives pollen. The style is a long tube-like structure that connects the stigma to the ovary. The ovary contains the ovules, which are the female gametes that develop into seeds after fertilization.

5. Receptacle: The receptacle is the base of the flower where all the other parts are attached. It provides support and protection for the reproductive organs.

Plant Reproduction

The flower plays a crucial role in plant reproduction by facilitating the process of pollination and fertilization. Pollination occurs when pollen grains are transferred from the anther of a stamen to the stigma of a carpel. This can happen through various means, including wind, water, or the assistance of pollinators.

Once the pollen grain lands on the stigma, it germinates and grows a pollen tube down through the style, eventually reaching the ovary. The male gametes inside the pollen grain travel down the pollen tube and fertilize the ovules inside the ovary. This process leads to the formation of seeds.

After fertilization, the ovary develops into a fruit, which protects the seeds and aids in their dispersal. The seeds can then germinate and grow into new plants, continuing the life cycle.

In conclusion, the metamorphosed part of the shoot that is meant for plant reproduction is the flower. Flowers are the reproductive structures of angiosperms and consist of various parts, including petals, sepals, stamens, carpels, and the receptacle. The flower plays a crucial role in facilitating pollination, fertilization, and the formation of seeds, which are essential for plant reproduction and the continuation of the plant life cycle.

Micropropagation by plant tissue culture has the advantage of producing virus-free clones by raising callus from shoot apex. This technique is useful for obtaining disease-free plants.

Flowers typically have four whorls: sepals, petals, stamens, and carpels. These whorls together make up the floral structure and are involved in the reproductive process.

The primary function of roots in plants is to anchor the plant securely in the soil, providing stability and support. Additionally, roots are responsible for absorbing water and essential minerals from the soil, which are then transported to the rest of the plant. While roots play a role in nutrient storage, their fundamental function is to ensure the plant's structural integrity and facilitate its water and mineral uptake.

Transpiration
Transpiration is the process by which excess water in the form of vapor is lost through the aerial parts of a plant, mainly through the stomata on the leaves. This process is crucial for plants as it helps in cooling the plant, transporting nutrients and minerals, and maintaining turgidity in the cells.
Significance of Transpiration
- **Cooling mechanism**: Transpiration helps in cooling the plant by releasing excess heat during the process of water vaporization.
- **Nutrient transport**: Water and minerals absorbed by the roots are transported to different parts of the plant through the process of transpiration.
- **Maintaining turgidity**: Transpiration helps in maintaining turgidity in the plant cells, which is essential for plant structure and growth.
Mechanism of Transpiration
- **Stomata**: Tiny openings on the surface of leaves through which water vapor escapes.
- **Guard cells**: Surround the stomata and regulate their opening and closing to control transpiration.
- **Root pressure and cohesion-tension theory**: Water is absorbed by roots and transported to leaves, where it evaporates through stomata due to differences in water potential.
Factors affecting Transpiration
- **Environmental conditions**: Temperature, humidity, wind speed, and light intensity influence the rate of transpiration.
- **Plant factors**: Number and distribution of stomata, leaf surface area, and plant species affect transpiration rates.
Conclusion
Transpiration is a vital process for plants as it helps in maintaining water balance, nutrient transport, and overall plant health. Understanding the mechanisms and factors influencing transpiration is crucial for effective plant growth and development.