Page 49 - ScienceStd4

within two months depending on the environmental conditions
such as temperature. Nymphs are small with soft, outer layer
and do not have wings. After three months, the nymphs grow
into adult cockroaches. See Figure 7.
FOR ONLINE READING ONLY

Egg

Adult

Nymph

Figure 7: Stages of cockroach development

Regular cleaning and organising of clothes and other items can
remove cockroach breeding and hiding places. You can also
use insecticides to kill cockroaches.

Revision exercise

Section A

1. Match the disease in Section A with its symptoms in
Section B.

No. Section A Section B
(a) Malaria (i) Causes rashes that turn into blisters

(b) Chickenpox (ii) Coughing for two weeks or more

(c) Asthma (iii) Frequent urination

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