K.C.S.E Biology Q & A - MODEL 2019PP1QN10

K.C.S.E Biology Q & A - MODEL 2019PP1QN10

In an investigation, students set up the apparatus below in the laboratory and made observations after 72 hours.

​(a) Explain how inclusion of the following components would affect the mouse in the experiment:
(i) light 
(ii) sodium hydroxide solution 
(b) State why the students preferred to use a bell jar and not a tin box in the experiment.

answers

​.(a) i) light enables the potted plant to photosynthesize; producing oxygen which is
Inhaled by the mouse, (sustaining it); the illuminated light can further affect /alter some photosynthesized processes in the mouse as a result of constant direct beam of light.
(ii) Absorbs carbon(iv)oxide (mainly exhaled by the mouse); while at the same time deny the plant the needed raw material, carbon (iv) oxide to photosynthesize hence suffocating the mouse/ emitting its survival / no oxygen;
(b) bell jar is transparent, allow penetration of light for the plant to photosynthesize; tin box is opaque hence does not allow photosynthesis/ could easily heat up altering the temperature inside for the mouse/ plant;