(b) Give reasons for the following:
(iii) Potato cubes when placed in water become firm and increase in size.
Potato cubes absorb water by the process of endosmosis and the cell membrane
acts as a semi-permeable membrane. Due to endosmosis, the potato cubes increase
in size. The turgor pressure increases due to endosmosis of water and thus the cells become turgid and the potato becomes firm.
Give reasons for the following:
(iv) A matured mammalian erythrocyte lacks nucleus and mitochondria.
Give reasons for the following:
People living in hilly regions usually suffer from simple goitre.
With reference to the functioning of the eye, answer the following questions:
(iv) Name the cells of the retina and their respective pigments which get activated (1)
in dark and (2) in light
With reference to the human ear, answer the following questions:
(i) Give the technical term for the structure found in the inner ear.
With reference to the human ear, answer the following questions:
(ii) Name the three small bones present in the middle ear. What is the biological term
for them collectively?
Give reasons for the following:
(v) Photosynthesis is considered as a process supporting all life on Earth.
With reference to the functioning of the eye, answer the following questions:
(i) What is power of accommodation of the eye?
