Excretory And Reproductive System

1. The nephron is the microscopic structural and functional unit of the: [S.S.C. Online C.H.S.L. (T-I) 11.08.2021 (Shift-II)]

(a) Liver
(b) Kidney
(c) Heart
(d) Lung

Correct Answer: (b) Kidney

Solution:The nephron is the basic structural and functional unit of the kidney. Its chief function is to regulate the concentration of water and soluble substances like sodium salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.

2. ______ is the structural and functional unit of kidney. [S.S.C. Online CGL (T-I) 13.08.2021 (Shift-I)]

(a) Ureter
(b) Nephron
(c) Cortex
(d) Medulla

Correct Answer: (b) Nephron

3. Nephrons are associated with— [S.S.C. Online MTS (T-I) 17.09.2017 (Shift-I)]

(a) Respiratory system
(b) Nervous system
(c) Circulatory system
(d) Excretory system

Correct Answer: (d) Excretory system

Solution:The excretory system is responsible for removing waste products and excess substances from the body to maintain homeostasis. Kidneys, with their millions of nephrons, are the primary organs of the excretory (or urinary) system, filtering blood and producing urine.

4. Which is not a part of urinary system? [S.S.C Online Constable GD 12.02.2019 (Shift-II)]

(a) Urethra
(b) Ureters
(c) Bronchi
(d) Urinary bladder

Correct Answer: (c) Bronchi

Solution:The urinary system consists of the kidneys (which produce urine), ureters (tubes that carry urine from kidneys to the bladder), the urinary bladder (stores urine), and the urethra (tube that excretes urine from the body). Bronchi are part of the respiratory system, specifically the air passages within the lungs.

5. In mammals, an important role of excretion is played by ______ . [S.S.C. Online Graduate Level (T-I) 29.08.2016 (Shift-III)]

(a) Large intestine
(b) Kidneys
(c) Lungs
(d) Liver

Correct Answer: (b) Kidneys

Solution:The kidneys are the main organs of excretion in mammals. They filter blood to remove metabolic wastes (like urea, creatinine, uric acid), excess salts, and water, forming urine. While lungs excrete carbon dioxide and the liver processes toxins, the kidneys are central to maintaining blood purity and fluid balance.

6. The yellow colour of human urine is due to : [S.S.C. Online CHSL (T-I) 22.01.2017 (Shift-I)]

(a) Bile Salts
(b) Cholesterol
(c) Lymph
(d) Urochrome

Correct Answer: (d) Urochrome

Solution:Urochrome (also known as urobilin) is a yellow pigment that is a breakdown product of heme, which comes from the breakdown of red blood cells. The concentration of urochrome determines the intensity of the yellow color of urine; the more concentrated the urine, the darker yellow it appears.

7. How many arteries are there in an umbilical cord? [S.S.C. Online CGL (T-I) 13.08.2021 (Shift-III)]

(a) Two
(b) One
(c) Four
(d) Three

Correct Answer: (a) Two

Solution:A typical umbilical cord contains two umbilical arteries and one umbilical vein, surrounded by Wharton's jelly. The two arteries carry deoxygenated blood and waste products from the fetus to the placenta, while the single vein carries oxygenated blood and nutrients from the placenta to the fetus.

8. Menopause is the stage in women when ______ . [S.S.C. Online MTS (T-I) 20.09.2017 (Shift-II)]

(a) Menstrual cycle begins
(b) Puberty begins
(c) Menstrual cycle stops and fertility is impaired
(d) Menstrual cycle ends

Correct Answer: (c) Menstrual cycle stops and fertility is impaired

Solution:Menopause is the stage in women when menstrual cycle stops and fertility is impaired. Menopause is the time that marks the end of your menstrual cycles. It’s diagnosed after you’ve gone 12 months without a menstrual period. Menopause can happen in your 40s or 50s.

9. Which of the following is the primary sex organ in females? [S.S.C. Online Graduate Level (T-I) 6.03.2020 (Shift-I)]

(a) Uterus
(b) Fallopian Tube
(c) Ovary
(d) Vagina

Correct Answer: (c) Ovary

Solution:Primary sex organs (gonads) are those that produce gametes (sex cells) and sex hormones. In females, the ovaries produce eggs (ova) and female hormones like estrogen and progesterone. The uterus, fallopian tubes, and vagina are secondary sex organs involved in reproduction but do not produce gametes.

10. What is the female gamete called? [S.S.C. Online C.P.O.S.I. (T-I) 7.01.2017 (Shift-I)]

(a) Zygote
(b) Egg
(c) Sperm
(d) Embryo

Correct Answer: (b) Egg

Solution:Female gametes are called ova or egg cells, and male gametes are called sperm. Gametes are haploid cells, and each cell carries only one copy of each chromosome. These reproductive cells are produced through a type of cell division called meiosis.