Free Growth and Development MCQs with Answers

191. Meristematic tissue responsible for increase in girth of tree trunk is

• A. Intercalary meristem
• B. Lateral meristem
• C. Phellogen
• D. Apical meristem

Explanation: (b): Lateral meristems are the meristems which are present along the lateral sides of stem and roots. They divide only in radial direction. Intrastelar or vascular cambium ring formed by intra­fascicular (also called fascicular) and inter­fascicular cambium; and cork cambium (phellogen) are examples of this type of meristem. These meristems are responsible for increase in girth of stem and roots.

192. Root hair develop from the region of

• A. Elongation
• B. Root cap
• C. Meristematic activity
• D. Maturation

Explanation: (d): Root hair are lateral tubular outgrowths that develop from the outer cells of zone of maturation or root hair zone.

193. Deciduous plants lose their leaves each year in response to changes in the day length.The biorhythm exemplified in the given statement is

• A. Circadian rhythm
• B. Circannual rhythm
• C. Circatidal rhythm
• D. Circalunar rhythm

Explanation: The correct answer is Option B: circannual rhythm. This is because deciduous plants lose their leaves once a year, which aligns with the annual cycle characteristic of circannual rhythms.Option A, circadian rhythm, is incorrect because it involves daily cycles. Option C, circatidal rhythm, is incorrect because it involves tidal patterns, typically occurring multiple times a day. Option D, circalunar rhythm, is incorrect because it involves monthly cycles related to the lunar phases, not annual changes.

194. Which one of the following pairs, is not correctly matched?

• A. Gibberellins, Leaf fall
• B. Cytokinin, Cell division
• C. IAA, Cell wall elongation
• D. Abscissic acid, Stomatal closure

Explanation: Gibberellins promote leaf growth and fruit growth and sometimes can induce parthenocarpy.

195. How does pruning help in making the hedge dense ?

• A. It releases wound hormones.
• B. It induces the differentiation of new shoots
• C. It frees axillary buds from apical dominance.
• D. The apical shoot grows faster after pruning.

Explanation: (c) : Prunning is the process of cutting shoot tips to promote lateral growth of branches. Removal of shoot tips involves removal of apical buds. In the shoot tips auxins are produced. Auxins are growth promoting phytohormones. They cause apical dominance by promoting the growth of apical buds and suppressing the growth of axillary buds. So when the auxins produced in the shoot tips are removed by decapitation it results in lateral growth and plants thus show bushy appearance. This is because of a relatively high concentration of auxin in the apical bud than in the lateral buds.

196. In the higher plants, growth is confined to certain regions called the:

• A. Meristems
• B. Epistcms
• C. Peristems
• D. Mesostems
• E. Cyclostems

Explanation: "The explanation for this question will be added soon!".

197. Most of the enzyme work optimally in between :

• A. 5°C to 10°C
• B. 10°C to 15°C
• C. 18°C to 28°C
• D. 28°C to 30°C
• E. 25°C to 37°C

Explanation: Most of the enzyme work optimally in between 25°C to 37°C. Many enzymes work optimally within a specific temperature range, typically between 25°C to 37°C (77°F to 98.6°F), which is roughly the range of normal human body temperature. This range is often referred to as the "optimal temperature" for enzyme activity. However, it's essential to note that the optimal temperature can vary depending on the specific enzyme and the organism from which it originates. In various industrial processes, enzymes are used as biocatalysts. The temperature at which enzymes are used in industrial applications is often carefully controlled to maximize their efficiency and productivity.Enzymes are biological catalysts that facilitate chemical reactions in living organisms. They have evolved to function best at the temperatures commonly found in their natural environments.

198. Plant hormone "AUXIN" is:

• A. Acetic Acid
• B. Ethyl Acetic Acid
• C. Methyl acetic Acid
• D. Indole Acetic Acid
• E. None of these

Explanation: Plant hormone "AUXIN" is indole Acetic Acid. Indole-3-acetic acid (IAA) is a naturally occurring plant hormone and a member of the auxin class of phytohormones. Auxins, including IAA, play a crucial role in regulating various aspects of plant growth and development. IAA is often considered the primary and most widely studied auxin in plants. IAA promotes cell elongation in the growing tips of plant shoots, stems, and roots. It helps cells to expand and increase in size, leading to the growth of plant organs.IAA is involved in apical dominance, where the apical bud (the bud at the tip of the shoot) inhibits the growth of lateral buds.

199. The removal of apex releases the lateral buds from apical dominance is called:

• A. Inhibitory Effects
• B. Compensatory Effects
• C. Compression Effects
• D. Comprehension Effect
• E. Conversion Effects

Explanation: The removal of apex releases the lateral buds from apical dominance is called compensatory Effects. "Compensatory effects" refer to the mechanisms or processes by which an organism, system, or individual compensates for a change or disturbance, often to maintain a state of equilibrium or balance. These effects can be observed in various contexts, including biology, ecology, economics, and human behavior.Compensatory effects can have a profound impact on the dynamics and stability of various systems, as they often represent mechanisms to maintain balance or adapt to changes. Understanding these effects is essential in fields like ecology, economics, and medicine to make informed decisions and predictions about how systems respond to disturbances or changes.

200. A structure established between the uterine and foetal tissues for the exchange of oxygen, carbon dioxide, waste, nutrients and other materials is:

• A. Amnion
• B. Placenta
• C. Endometrium
• D. Uterus

Explanation: The placenta is defined as temporary intimate mechanical and the physiological connection between foetus and maternal tissue for the nutrition, respiration and excretion of the foetus. Human placenta consists of chorion only. The placenta is fully formed by the end of the third month and maintains pregnancy. In the placenta, the foetal blood comes very close to the maternal blood and this permits the exchange of material between the two. Food, water, mineral salt, vitamins, hormone antibodies and oxygen pass from the maternal blood into the foetal blood, and foetal metabolic waste, such as carbon dioxide, and urea, also water and hormones, pass into the maternal blood.