B is the most effective and feasible, and it prevents the initial introdution of the species
Answer:
The cells present in the stem are part of the xylem and phloem conductive tissues. They are characterized by being elongated and in tubular form because they transport the substances, the xylem transports water and inorganic mineral sales that the root absorbs from the soil. The phloem is responsible for transporting substances synthesized in photosynthesis.
Its tubular and elongated shape facilitates the transport of these substances
The reasons are:
- the blood is very low on nutrition
- the leech is not feeding itself regularly
The leech slows it metabolism a lot, so it can survive on very low nutrition. The blood is very low on nutrition, and it is the leech's food source, so the evolution made it preserve energy.
The leach doesn't have the opportunity to feed itself on regular basis, so it takes maximum advantage of any opportunity and consumes as much blood as possible so that it can survive long term when it will not have food at disposal.
