The correct answer is: A. minus end; dynein
Microtubules are cytoskeletal fibers that have an important role in the intracellular transport (movement of vesicles within the cell) and in the mitotic spindle during mitosis. The plus end of the microtubules extend through the periphery of the cells while the minus ends are anchored within the centrosome.
Necessary proteins for the vesicle’s movement are motor proteins:
• kinesin which is positive end directed
• dynein which is negative end directed
So, beside vesicles these proteins are also involved in organelles’ transport in opposite directions through the cytoplasm.
Consequently plant roots will get more moisture with less effort. It also improves soil structure due to alternate drying and cooling and soil aeration which helps in multiplication of micro-organisms. This is the reason that farmers plough their field during summer.
Hope this helps!
~ Kana ^^
Xylem is one of the two types of transport tissue in vascular plants, phloem being the other. The basic function of xylem is to transport water from roots to stems and leaves, but it also transports nutrients.
Their beaks could have adapted over time to help them better survive in their environment.
The first step in designing an experiment is the form a testable question.