Answer:
They have helical thickening of lignin in their walls to prevent collapse
Explanation:
the primary function of Xylem and its conducting vessels tracheids is to provide support and tranport water and minerals in plants.
Xylem vessels have layers of dead materials in the walls called LIGNIN. Lignin is a polymer; a very strong, hard materials that stop water passage through it,because it contains dead cells,
Therefore the presence of deposit of these strong impermeable, ligified walls in its walls prevent its collapse during mass flow of water of transpiration pull.
The correct answer is: gaps left at the 5' end of the lagging strand
Telomeres are repetitive regions at the very ends of chromosomes found in eukaryotic organisms. The “problem” with telomeres is that the DNA replication cannot be fully finished in each round which result in a slow, gradual shortening of the chromosome.
Gaps at the end of lagging strand are formed because lagging strand is synthesized via Okazaki fragments (small DNA fragments). So, when replication fork during replication reaches the end of the chromosome, a short stretch of DNA does not get covered by an Okazaki fragment and consequently remains uncopied in each round of replication, leaving a single-stranded overhang.
Telomerase is an enzyme that solves this problem by extending the telomeres of chromosomes.
The embedded proteins <u>allow specific substances to flow into the cell</u>.The phospholipid bilayer forms a stable barrier between two aqueous compartment.They embedded proteins carry the selective transportation of molecules and ensure their is cell to cell recognition.
The only one that should not be selected is "are carried on genes" since genes are segments of DNA that code for something. Like one of the answers said, chromosomes carry thousands of genes, making the statement, "are carried on genes," completely false.
