The hydrogen bonding that created its hexagonal shape....the molecules get closer together and there will be more hydrogen bonding making it solid
A true-breeding plant is one that, when self-fertilized, only produces offspring with the same traits. True-breeding organisms are genetically identical and have identical alleles for specified traits. It is a kind of breeding wherein the parents would produce offspring that would carry the same phenotype. Basically true means identical or same. Hope this somewhat helped :)
Explanation:
Cell membranes are selectively permeable. Some solutes cross the membrane freely, some cross with assistance, and others do not cross at all. A few lipophilic substances move freely across the cell membrane by passive diffusion. ... Large molecules do not cross intact cell membranes, except in certain special cases.
