BPSC CCE Prelims
Biology Previous Year Questions (PYQs)

Detailed Explanation:

Water moves from soil into plant roots through osmosis, a process where water molecules pass through a semi-permeable membrane (root cell walls) from a region of higher water concentration (soil) to lower water concentration (root cells).

Diffusion involves movement of particles from high to low concentration but does not require a semi-permeable membrane. Absorption is a general term for uptake, while transpiration is water loss from leaves through stomata—not water uptake.

Therefore, osmosis is the specific physical process for water uptake by roots, making Option 4 the correct answer.

Detailed Explanation:

During photosynthesis (daytime), plants absorb CO₂ and release O₂. At night, photosynthesis stops, but respiration continues—plants absorb O₂ and release CO₂, just like animals.

In enclosed or poorly ventilated spaces, this can slightly increase CO₂ levels and reduce oxygen concentration, making it uncomfortable to sleep under trees indoors or in confined areas.

Therefore, trees liberate carbon dioxide at night through respiration, making Option 3 the correct answer.

Detailed Explanation:

The stem of a plant serves multiple functions: it transports water and nutrients from roots to leaves, distributes food (prepared by leaves during photosynthesis) to all parts, and stores food in the form of starch in tissues like parenchyma (e.g., potato, ginger, sugarcane stems).

While stems contribute to plant shape and contain lenticels for respiration, and green stems assist in photosynthesis, the question explicitly asks what stem helps with beyond distribution—making food storage the primary additional function.

Therefore, storing food is the key function alongside distribution, making Option 1 the correct answer.

Detailed Explanation:

Blood transfusion compatibility requires matching both ABO blood type and Rh factor to prevent immune reactions and hemolysis.

The Rh factor (Rh+ or Rh−) is a critical antigen on red blood cells; mismatched transfusion can trigger severe immune responses, especially in Rh-negative recipients receiving Rh-positive blood.

White cell count, red cell count, and donor race are not compatibility determinants for transfusion safety.

Therefore, Rh factor compatibility is essential, making Option 1 the correct answer.

Detailed Explanation:

The pituitary gland is a pea-sized endocrine gland located at the base of the brain, attached to the hypothalamus by a stalk called the infundibulum. It sits in a bony cavity called the sella turcica.

Known as the "master gland," it regulates various hormonal functions including growth, metabolism, reproduction, and stress response by secreting hormones like GH, TSH, ACTH, FSH, LH, and prolactin.

Therefore, the pituitary gland is located in the brain, making Option 4 the correct answer.

Detailed Explanation:

Ultrasonic waves (high-frequency sound waves above 20 kHz) are used in ultrasound imaging to monitor fetal growth in the womb. These waves are safe, non-invasive, and produce real-time images by reflecting off tissues.

X-rays involve ionizing radiation harmful to the fetus, microwaves are used in communication/heating, and ultraviolet rays cause skin damage—none are suitable for prenatal imaging.

Therefore, Ultrasonic waves are used for fetal imaging, making Option 3 the correct answer.

Detailed Explanation:

AB blood group individuals possess both A and B antigens on their red blood cells but have no anti-A or anti-B antibodies in their plasma, allowing them to receive blood from all ABO groups without immune rejection.

O blood group is the universal donor (lacks A/B antigens), while A and B groups have specific antibodies that would attack incompatible blood types.

Therefore, AB can accept blood from all groups, making Option 3 the correct answer.