10th Science Book Back Answers Unit 16 – Plant and Animal Hormones:

Samacheer Kalvi 10th Standard Science Book Back Questions with Answers PDF uploaded and the same is given below. Class-tenth candidates and those preparing for TNPSC exams can check the New Science Book Back Question and Answers PDF below.  Samacheer Kalvi Class 10th Std Science Book Back Answers Biology Unit 16 – Plant and Animal Hormones Solutions are available below. Complete solutions for all 23 Units’ book back questions with a solutions guide uploaded and available on our site. Check the complete Samacheer Kalvi 10th Science Unit 16 Answers below:

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Samacheer Kalvi 10th Science Book Back Answers Biology Unit 16 – Plant and Animal Hormones:

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10th Science – Biology

Unit 16 – Plant and Animal Hormones

I. Choose the best answer:

1. Gibberellins cause:
a) Shortening of genetically tall plants    b) Elongation of dwarf plants
c) Promotion of rooting                              d) Yellowing of young leaves
Ans: (b) Elongation of dwarf plants

2. The hormone which has a positive effect on apical dominance is:
a) Cytokinin   b) Auxin   c) Gibberellin   d) Ethylene
Ans: (b) Auxin

3. Which one of the following hormones is naturally not found in plants:
a) 2, 4–D b) G A 3 c) Gibberellin d) IAA
Ans: (a) 2, 4–D

4. Avena coleoptiles est was conducted by
a) Darwin b) N. Smit c) Paal d) F.W. Went
Ans: (d) F.W. Went

5. To increase the sugar production in sugarcanes they are sprayed with
a) Auxin    b) Cytokinin    c) Gibberellins    d) Ethylene
Ans: (d) Ethylene

6. LH is secreted by
a) Adrenal gland b) Thyroid gland c) Anterior pituitary d) Hypothalamus
Ans: (c) Anterior pituitary

7. Identify the exocrine gland
a) Pituitary gland b) Adrenal gland c) Salivary gland d) Thyroid gland
Ans: (c) Salivary gland

8. Which organ acts as both exocrine gland as well as endocrine gland
a) Pancreas   b) Kidney    c) Liver    d) Lungs
Ans: (a) Pancreas

9. Which one is referred to as “Master Gland”?
a) Pineal galnd b) Pituitary gland c) Thyroid gland d) Adrenal gland
Ans: (b) Pituitary gland

II. Fill in the blanks

1. _______causes cell elongation, and apical dominance and prevents abscission. Ans: Auxin
2. _______is a gaseous hormone involved in the abscission of organs and acceleration of fruit ripening. Ans: Ethylene
3. _______causes stomatal closure. Ans: Abscisic acid
4. Gibberellins induce stem elongation in ______plants. Ans: Rosette
5. The hormone which has a negative effect on apical dominance is ______. Ans: Cytokinin
6. Calcium metabolism of the body is controlled by ______. Ans: Parathormone
7. In the islets of Langerhans, beta cells secrete _____. Ans: Insulin.
8. The growth and functions of the thyroid gland are controlled by ______. Ans: Hormone T₃ and T₄
9. Decreased secretion of thyroid hormones in children leads to _____.  Answer: Cretinism.

III. Match the following:

Question 1.
(a) Match the Column I with Columns II and III.

Answer:

(b) Match the following hormones with their deficiency states.

Answers:

1. (c) Simple goitre
2. (e) Diabetes mellitus
3. (b) Tetany
4. (a) Acromegaly
5. (d) Diabetes insipidus

IV. True or False (Correct the Statement if it is false)

1. A plant hormone concerned with stimulation of cell division and promotion of nutrient mobilization is cytokinin.
Ans: True.

2. Gibberellins cause parthenocarpy in tomatoes.
Ans: True.

3. Ethylene retards the senescence of leaves, flowers, and fruits.
Ans: False. Ethylene hastens the senescence of leaves, flowers, and fruits.

4. Exophthalmic goiter is due to the over secretion of thyroxine.
Ans: True.

5. Pituitary gland is divided into four lobes.
Ans: False. Pituitary gland is divided into two lobes.

6. Estrogen is secreted by the corpus luteum.
Ans: False. Estrogen is secreted by Graafian follicles.

V. Assertion and Reason
Direction: In each of the following questions, a statement of Assertion is given and a corresponding statement of reason is given just below it. Of the statements given below, mark the correct answer as
a) If both A and R are true and R is the correct explanation of A.
b) If both A and R are true but R is not the correct explanation of A.
c) If A is true but R is false.
d) If both A and R are false.

1. Assertion: Application of cytokinin to marked vegetables can keep them fresh for
several days.
Reason: Cytokinins delay senescence of leaves and other organs by mobilization of nutrients.
Ans: (a) Both A and R are true and R is the correct explanation of A

2. Assertion (A): Pituitary gland is referred as the “Master gland”.
Reason (R): It controls the functioning of other endocrine glands.
Ans: (a) Both A and R are true and R is the correct explanation of A

3. Assertion (A):- Diabetes mellitus increases blood sugar levels.
Reason (R):- Insulin decreases blood sugar levels.
Ans: (b) Both A and R are true but R is not the correct explanation of A

Other Important links for 10th Science Book Answers Solutions:

For the 10th Standard Science Unit 17 book back question and answers solutions PDF, check the link – Samacheer kalvi 10th Science Unit 17 – Reproduction In Plants And Animals

Click here for the complete Samacheer Kalvi 10th Science Book Back Solution Guide PDF – 10th Science Book Back Solutions