[5 marks Questions]

Question 15 Marks

i. Define a reflex arc. Why have reflex arcs evolved in animals? Trace the sequence of events which occur, when you suddenly touch a hot object.
ii. Name the part of nervous system which helps in communication between the central nervous system and other parts of the body. What are the two components of this system?

Answer

i. The pathway in which impulses travel during the reflex action is called a reflex arc. Because the thinking part of the brain is not fast enough/for quick response to avoid injury. Reflex arc:

ii. Peripheral Nervous System
Components: Cranial Nerves; Spinal Nerves

View full question & answer→

Question 25 Marks

a. What is puberty? Write any two changes that occur in boys during early teenage years.
b. List two functions performed by testis in human males.
Mention one role each of (i) Vas deferens, (ii) Seminal Vesicle (iii) Urethra and (iv) Scrotum in human male reproductive system.

Answer

a. When the rate of general body growth begins to slow down and reproductive tissue begins to mature.
In boys - New thick hair growth on face, voice begins to crack, penis begins to enlarge and become erect.
b. Testis - Formation of sperms, Secretion of hormone testosterone
Role of:
i. Vas deferens - Delivery of sperms from testes to urethra.
ii. Seminal vesicle - Provides nutrition to sperms /makes the transport(movement) of sperms easier.
iii. Urethra - Common passage for sperms and urine.
iv. Scrotum - Providing required temperature for sperm formation

View full question & answer→

Science [5 marks Questions]

Test yourself on this topic