Question

(a) The number of new infections of HIV each year in one country is recorded.
Fig. 4.1 is a bar chart of the results.

(i) Calculate the percentage increase in cases between 1998 and 2002 shown in Fig. 4.1.
number of new HIV infections in 1998 ……………………………………………………………………
number of new HIV infections in 2002 ……………………………………………………………………
                                          percentage increase = ………………………………………………….. %

(ii) Suggest three reasons for the change in the number of new HIV infections between 2002 and 2008 in Fig. 4.1.
1 …………………………………………………………………………

2 …………………………………………………………………………
3 …………………………………………………………………………

(b) Fig. 4.2 is a photomicrograph of blood.

State the names and functions of the two types of cells, A and B, shown in Fig. 4.2.
cell type A
name …………………………………………………………………………

function …………………………………………………………………………
cell type B
name …………………………………………………………………………

function …………………………………………………………………………
(c) State the name of the organ responsible for pumping the blood around the body.

▶️Answer/Explanation

Ans : 4(a)(i) infections in 1998 – 4600 and infections in 2002 – 7000 ; ((7000 – 4600) / 4600) × 100 = 52 ;
4(a)(ii) any three from:
increased education / awareness ;
use of condoms ;
screening of blood transfusions ;
use of clean needles ;
increased screening ;
AVP ;
4(b) cell type A
red blood cell ;
transport of oxygen ;
cell type B
white blood cell ;
production of antibodies / phagocytosis ;

4(c) heart ;