What is the primary job of Merismatic tissue?

Primary meristematic tissue helps the plant increase in length or vertical growth, meaning it helps the plant grow up toward the sun and down into the soil. Secondary meristematic tissue helps the plant increase the girth or lateral growth of its stems, branches, and roots

Explanation:

thinking it would be physical characteristics

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