Because they do not have an immune system, don't have noses, don't have mouths, and just plain do not have the same functions as animals, insects, or humans. They don't have a heart or a brain, which means they can't catch a cold. They can get diseases however.
Completely wipe out one of the other species.
-- CocaBeanz has got your back :)
Answer:
In roots, the vascular tissues, i.e., xylem and phloem, are found in the central vascular cylinder, while in stems these tissues are dispersed throughout the stem, generally arranged as a ring towards the outside of the stem (epidermis)
Explanation:
Vascular plants have two different transport tissues: xylem and phloem. The xylem transports water from roots to stems and leaves, while the phloem transports food (i.e. dissolved sugars) from the leaves to all parts of the plant. In roots, vascular tissues form a central core in order to withstand stretching forces. Moreover, in stems, vascular tissues are dispersed (generally concentrated towards the epidermis), in an arrangement that enables them to resist compression and bending forces.
Allan already had a heart attack and can try to prevent another one by changing the diet, exercising, or even quit smoking, but there are non-modifiable risks such as age, sex and generic heritage, so If Allan is over 40 years old, male or comes from a family with heart diseases, Allan needs to be extra careful because those factors cannot be changed no matter how the way of life is changed.
look at the photo, it wouldn't let me type it, sorry :-/