The economist thomas malthus suggested that
a people die faster than babies are born
b there were soon be insufficient food for the growing human population
c in the 1700s, england needed more housing
d the majority of a species offspring die

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By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.