Scientists Measured the Pressure in the Xylem of Redwood Trees

question 16

Multiple Choice

Scientists measured the pressure in the xylem of redwood trees at different heights and found that the higher they made their measurements,the lower the pressure.They extrapolated this to a pressure of zero,and concluded that the tallest a tree could grow is 122-130 meters.The tallest known tree on Earth is 112.7 meters.Which of the following most likely limits the height of trees?

• A)the amount of transpiration in leaves
• B)the amount of photosynthesis in leaves
• C)the amount of energy needed to pump water to the tops of the trees
• D)the strength of water cohesion
• E)the ability to take up CO₂

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Definitions:

Dizygotic Twins

Also known as fraternal twins, are siblings born at the same time as a result of the fertilization of two different eggs by two different sperms.

Genes

Units of heredity made up of DNA that are responsible for the inherited characteristics in living organisms, dictating the development and functioning of organisms.

Selective Breeding

The process by which humans use animal and plant breeding techniques to selectively develop particular phenotypic traits by choosing which typically animal or plant males and females will sexually reproduce.

Eugenics

A set of beliefs and practices aimed at improving the genetic quality of the human population, historically associated with morally controversial methods and ideologies.