Which of the following is an example of imbibition?

1.  Uptake of water by roothair

2.  Exchange of gases in stomata

3.  Swelling of seed when put in soil

4.  Opening of stomata

(c) Swelling of seed in soil is an example of imbibition. Imbibition is a type of diffusion process along the concentration gradient enabling the solid to absorb water and increase in volume.When Seed is put in the soil it absorbs water which activate enzymes present in seed and this induces the seed germination.
exchange The other options, i.e., uptake of water by root hair is an example of absorption,
 in of gases turgor stomata is an example of diffusion and Opening of stomata is an  example of turgot pressure or turgidily
Page 183, XI NCERT