What is the significance of secondary growth in plants? a: to support the extra weight of the tree due to an increase in its height and to prevent it from collapsing b: to support the extra weight of the tree due to an increase in its breadth and to prevent it from collapsing c: to support the roots due to an increase in their number and to prevent the tree from collapsing

there's the proffessional site that will you.

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

hope this