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Why do different blood vessels have different lumen sizes (relative to their overall size)?

Lumen sizes in blood vessels differ due to the differing functions of the vessels themselves. Arteries have to carry oxygenated blood away from the heart to the tissues at high pressure. Small lumen (relativ...
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Answered by Jessica S. • Biology tutor
82369 Views

Outline the role of adrenaline in the flight or fight response (4)

Adrenaline is released from the adrenal medulla in response to the activation of the sympathomedullary pathway, in response to acute stress. The direct effects of adrenaline include the increase of heart rat...
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Answered by Lucy R. • Psychology tutor
37319 Views

What is the difference between the preterite and imperfect past tenses?

The preterite is used to describe actions that were completed at a specific moment in the past. For example, "Ayer, Marina me pidió ir al cine". This action happened yesterday (ayer) and is not a c...
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Answered by Lexi J. • Spanish tutor
2202 Views

How do I differentiate something of the form a^x?

You should write a x as (e lna ) x = e xlna . ln(a) is a constant, so use the chain rule to differentiate this: lna(e xlna ) = lna(a x )
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Answered by Ilya S. • Maths tutor
4932 Views

Find the cross product of vectors a and b ( a x b ) where a = 3i + 6j + 4k and b = 6i - 2j + 0k.

a x b = 8i + 24j - 42k
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Answered by Isaac D. • Maths tutor
4504 Views