138 ELEMENTARY BOTANY 
1'oo high a temperature, as we have seen in the experiment of 
boiling seeds, kills and renders growth impossible. 
All these experiments show that a plant is affected by 
external conditions, such as light, temperature, moisture ; 
thus it can adapt itself to varying conditions. A land plant, 
for instance, does thrive if grown in water, its roots being 
able to adapt themselves to the different medium. This 
power of adaptability is characteristic of all living things. 
