Shortening of genetically tall plants

Plant and Animal Hormones Book Back One Mark Questions with Answers & Explanations (10th Standard Science)

Every Book Back multiple-choice question from Plant and Animal Hormones (10th Standard Science, Samacheer Kalvi) — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.

Answer key at a glance

Q1B Q2B Q3A Q4D Q5C Q6C Q7A Q8B

Gibberellins cause:

A. Shortening of genetically tall plants
B. Elongation of dwarf plantsCorrect
C. Promotion of rooting
D. Yellowing of young leaves

Explanation. Gibberellins induce internodal stem elongation in dwarf plants.

The hormone which has positive effect on apical dominance is:

A. Cytokinin
B. AuxinCorrect
C. Gibberellin
D. Ethylene

Explanation. Auxins produced by apical buds suppress the growth of lateral buds, causing apical dominance.

Which one of the following hormones is naturally not found in plants:

A. 2, 4-DCorrect
B. GA3
C. Gibberellin
D. IAA

Explanation. 2, 4-D (2,4-Dichlorophenoxyacetic acid) is a synthetic auxin and is not naturally produced by plants.

Avena coleoptile test was conducted by

A. Darwin
B. N. Smit
C. Paal
D. F.W. WentCorrect

Explanation. F.W. Went performed the Avena coleoptile curvature test to demonstrate the presence and action of auxin.

LH is secreted by

A. Adrenal gland
B. Thyroid gland
C. Anterior pituitaryCorrect
D. Hypothalamus

Explanation. Luteinizing Hormone (LH) is a gonadotropic hormone secreted by the anterior lobe of the pituitary gland.

Identify the exocrine gland

A. Pituitary gland
B. Adrenal gland
C. Salivary glandCorrect
D. Thyroid gland

Explanation. Salivary glands have ducts to release their secretions, classifying them as exocrine glands, whereas pituitary, adrenal, and thyroid glands are ductless endocrine glands.

Which organ acts as both exocrine gland as well as endocrine gland

A. PancreasCorrect
B. Kidney
C. Liver
D. Lungs

Explanation. The pancreas functions as both an exocrine gland (secreting digestive enzymes) and an endocrine gland (secreting hormones like insulin and glucagon).

Which one is referred as "Master Gland"?

A. Pineal gland
B. Pituitary glandCorrect
C. Thyroid gland
D. Adrenal gland

Explanation. The pituitary gland is known as the Master Gland because it regulates and controls the functions of other endocrine glands.

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About these Plant and Animal Hormones questions

These are the Book Back multiple-choice questions for Plant and Animal Hormones from the Tamil Nadu State Board (Samacheer Kalvi) 10th Standard Science syllabus. Each question shows the correct option and an original, step-by-step explanation so you understand the method, not just the answer. Use the answer key above to jump to any question, then take the practice test to check yourself under exam-like conditions.

Frequently asked questions

How many MCQs are there in Plant and Animal Hormones?

This chapter has 8 book-back multiple-choice questions, each with the correct answer and a step-by-step explanation.

Are these 10th Standard Science MCQs free to practise online?

Yes. Every question, answer and explanation here is free, and you can also take them as a timed practice test.

Where can I find the Plant and Animal Hormones book-back answers?

The correct option for each question is highlighted on this page with a worked explanation, plus a quick answer-key summary at the top.

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