Vidaara.orgClass 8 · Mathematics
CodeVID-M8-WS
Excretion and Nervous System — Practice Worksheet
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Choose the correct option (A, B, C or D) for each question.
- The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each)
50 × 1 = 50 marks
1.
The removal of harmful metabolic wastes from the body is called:
- A.Nutrition
- B.Excretion
- C.Respiration
- D.Digestion
2.
Plants release waste gases and excess water mainly through tiny pores called:
- A.Villi
- B.Stomata
- C.Nephrons
- D.Alveoli
3.
Which of these is a way plants remove stored wastes?
- A.Sweating
- B.Leaf fall and bark shedding
- C.Urinating
- D.Breathing through gills
4.
The milky fluid stored by some plants, used to make rubber, is:
- A.Resin
- B.Gum
- C.Latex
- D.Tannin
5.
Compared with animals, plants excrete in ways that are generally:
- A.More complex
- B.Simpler and slower
- C.Faster and forced
- D.Identical
6.
The main nitrogen-containing waste removed in human urine is:
- A.Glucose
- B.Urea
- C.Oxygen
- D.Protein
7.
The bean-shaped organs that filter the blood are the:
- A.Lungs
- B.Kidneys
- C.Liver lobes
- D.Bladders
8.
Urine is carried from the kidneys to the bladder by the:
- A.Urethra
- B.Ureters
- C.Trachea
- D.Veins
9.
The organ that stores urine until it is released is the:
- A.Kidney
- B.Ureter
- C.Urinary bladder
- D.Urethra
10.
The functional (filtering) unit of the kidney is the:
- A.Alveolus
- B.Nephron
- C.Neuron
- D.Villus
11.
Urine is formed in the nephron in how many main stages?
- A.One
- B.Two
- C.Three
- D.Five
12.
During filtration, which of these stays behind in the blood?
- A.Water
- B.Glucose
- C.Proteins
- D.Salts
13.
The stage in which useful substances like glucose are taken back into the blood is:
- A.Filtration
- B.Reabsorption
- C.Secretion
- D.Excretion
14.
The main waste substance dissolved in urine is:
- A.Glucose
- B.Urea
- C.Protein
- D.Starch
15.
The presence of glucose in urine may indicate the disease:
- A.Common cold
- B.Diabetes
- C.Malaria
- D.Anaemia
16.
The skin excretes wastes in the form of:
- A.Urine
- B.Sweat
- C.Bile
- D.Saliva
17.
Sweat is mostly made of:
- A.Salts
- B.Water
- C.Urea
- D.Glucose
18.
The control of the body's temperature is called:
- A.Excretion
- B.Thermoregulation
- C.Digestion
- D.Respiration
19.
The evaporation of sweat helps the body by:
- A.Adding heat
- B.Removing heat (cooling)
- C.Making urine
- D.Storing water
20.
When the body is too hot, the blood vessels near the skin:
- A.Widen to lose heat
- B.Narrow to keep heat
- C.Disappear
- D.Stop carrying blood
21.
The basic structural and functional unit of the nervous system is the:
- A.Nephron
- B.Neuron
- C.Alveolus
- D.Villus
22.
The short branching parts of a neuron that receive impulses are the:
- A.Axon
- B.Dendrites
- C.Myelin sheath
- D.Synapse
23.
The long fibre that carries the impulse away from the cell body is the:
- A.Dendrite
- B.Axon
- C.Cell body
- D.Pore
24.
The fatty covering that insulates the axon and speeds up the impulse is the:
- A.Myelin sheath
- B.Nucleus
- C.Cyton
- D.Synapse
25.
The tiny gap between two neurons is called a:
- A.Pore
- B.Synapse
- C.Valve
- D.Lumen
26.
Neurons that carry impulses from sense organs to the brain or spinal cord are:
- A.Motor neurons
- B.Sensory neurons
- C.Interneurons
- D.Relay only
27.
Motor neurons carry impulses from the central nervous system to the:
- A.Sense organs
- B.Effectors (muscles and glands)
- C.Skin only
- D.Eyes only
28.
Neurons that connect sensory and motor neurons within the CNS are:
- A.Sensory neurons
- B.Motor neurons
- C.Interneurons
- D.Receptors
29.
A muscle or gland that carries out a response is called a(n):
- A.Receptor
- B.Effector
- C.Stimulus
- D.Synapse
30.
Sensory neurons are also known as ______ neurons.
- A.Efferent
- B.Afferent
- C.Relay
- D.Motor
31.
A nerve impulse is best described as a tiny:
- A.Sound wave
- B.Electrical signal
- C.Drop of blood
- D.Muscle
32.
In a resting neuron, the inside is ______ compared with the outside.
- A.Slightly positive
- B.Slightly negative
- C.Exactly equal
- D.Has no charge
33.
The brief flip in which the inside of the neuron becomes positive is the:
- A.Resting potential
- B.Action potential
- C.Synapse
- D.Reflex
34.
The impulse is passed across the synapse by:
- A.Electricity jumping the gap
- B.Chemical neurotransmitters
- C.Blood
- D.Bones
35.
After an action potential passes, the neuron:
- A.Dies
- B.Returns to its resting state
- C.Stays positive forever
- D.Splits in two
36.
The two main divisions of the nervous system are the CNS and the:
- A.RBC
- B.PNS
- C.DNA
- D.ATP
37.
The central nervous system is made up of the brain and the:
- A.Heart
- B.Spinal cord
- C.Lungs
- D.Kidneys
38.
The network of nerves connecting the CNS to the whole body is the:
- A.Peripheral nervous system
- B.Autonomic only
- C.Skeleton
- D.Circulatory system
39.
The brain is protected inside the:
- A.Backbone
- B.Skull
- C.Ribcage
- D.Pelvis
40.
Automatic activities such as heartbeat and digestion are controlled by the:
- A.Autonomic nervous system
- B.Bones
- C.Skin
- D.Eyes
41.
The largest part of the brain, responsible for thinking and memory, is the:
- A.Cerebellum
- B.Cerebrum
- C.Medulla oblongata
- D.Spinal cord
42.
Which part of the brain controls balance, posture, and coordination of movement?
- A.Cerebrum
- B.Cerebellum
- C.Medulla oblongata
- D.Skull
43.
Involuntary actions such as heartbeat and breathing are controlled by the:
- A.Cerebrum
- B.Cerebellum
- C.Medulla oblongata
- D.Dendrites
44.
Voluntary actions, such as writing, are controlled mainly by the:
- A.Cerebrum
- B.Cerebellum
- C.Medulla oblongata
- D.Spinal cord
45.
The brain is protected and cushioned inside the:
- A.Backbone
- B.Skull
- C.Ribcage
- D.Pelvis
46.
A sudden, automatic, quick response to a stimulus is called a:
- A.Voluntary action
- B.Reflex action
- C.Habit
- D.Thought
47.
The pathway followed by a reflex action is called the:
- A.Nerve net
- B.Reflex arc
- C.Synapse
- D.Axon
48.
Reflex actions are controlled mainly by the:
- A.Cerebrum
- B.Spinal cord
- C.Cerebellum
- D.Skin
49.
Which of these is an example of a reflex action?
- A.Writing a letter
- B.Knee-jerk when tapped
- C.Singing a song
- D.Reading aloud
50.
Reflex actions are fast because the impulse:
- A.Travels to the brain and back
- B.Does not need to reach the brain first
- C.Stops at the skin
- D.Moves very slowly
Answer Key
Section A — Multiple Choice (1 mark each)
- (B) Excretion
- (B) Stomata
- (B) Leaf fall and bark shedding
- (C) Latex
- (B) Simpler and slower
- (B) Urea
- (B) Kidneys
- (B) Ureters
- (C) Urinary bladder
- (B) Nephron
- (C) Three
- (C) Proteins
- (B) Reabsorption
- (B) Urea
- (B) Diabetes
- (B) Sweat
- (B) Water
- (B) Thermoregulation
- (B) Removing heat (cooling)
- (A) Widen to lose heat
- (B) Neuron
- (B) Dendrites
- (B) Axon
- (A) Myelin sheath
- (B) Synapse
- (B) Sensory neurons
- (B) Effectors (muscles and glands)
- (C) Interneurons
- (B) Effector
- (B) Afferent
- (B) Electrical signal
- (B) Slightly negative
- (B) Action potential
- (B) Chemical neurotransmitters
- (B) Returns to its resting state
- (B) PNS
- (B) Spinal cord
- (A) Peripheral nervous system
- (B) Skull
- (A) Autonomic nervous system
- (B) Cerebrum
- (B) Cerebellum
- (C) Medulla oblongata
- (A) Cerebrum
- (B) Skull
- (B) Reflex action
- (B) Reflex arc
- (B) Spinal cord
- (B) Knee-jerk when tapped
- (B) Does not need to reach the brain first
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