If a human body requires artificial support for respiration, heartbeat, blood pressure and metabolism, at what point does it cease to be “vegetative” and become dead?

At brain death.

Explanation:

If an individual is awake but not conscious of what is happening in the surrounding environments the person is in the vegetative state.Such individual could respond to certain reflexes as eye blinking,withdrawal of hands in response to touch, ability to sleep and wake up at normal sensations.However, cognitive functions and sensory responses which are related to emotions are not responded to.It is different from Coma in which the individual lacks ability to be aware of the environments and  tom be awake or alert.

The vegetative state ends when brain deaths occurs.This is the state when all brain activities are lost permanently. Breathing seized,and contact with the external world is cut.Thus, the functions of the brain which were supported by artificial supports are lost because the parts of the brain which  control breathing,heartbeat ,and blood pressure are dead. Therefore, the life supports can not stimulate them to life

haploid cells;

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.