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I don't quite understand when to use the perfect tense vs the imperfect, could you help me please? (making the assumption they understand the conjugation rules already)

The imperfect tense is used to express things that 'were' happening or 'used to' happen. They may have taken place over a short period of time (a few seconds), or a prolonged period of time (several years) b...
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Answered by Tommy C. • French tutor
1979 Views

How is DNA replicated, and why is this method of replication important?

DNA is replicated in a semi-conservative manner, which means that both 'parental strands' are used as templates. This ensures that genetic information is passed onto offspring without any changes (diagram) D...
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Answered by Salima B. • Biology tutor
3229 Views

How do I integrate by substitution?

Let's take for example the integral 5x 2 (x 3 -4) 4 dx. This is very difficult and not at all nice to expand in terms of x, so we can effectively "create" a new variable, u, and set it to equal x 3...
EC
Answered by Edward C. • Maths tutor
4015 Views

Is AB perpendicular to BC where A =(2,0,-1), B=(4,3,-6) and C = (9,3,-4)

AB = B - A = (4,3,-6)- (2,0,-1) = (2 , 3 , -5)BC = C - B = (9,3,-4) - (4,3,-6) = (5, 0 , 2) If perpendicular "AB dot BC" should equal zeroAB dot BC = (2,3,-5) dot (5,0,2) = (2x5) + (3x0) + (-5x2) =...
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Answered by Syed Usman B. • Maths tutor
4219 Views

What is the difference between the function of platelets, white blood cells and red blood cells?

They are all components of blood. Platelets are small fragments of cells and help blood to form clots. This stops the body from bleeding when a blood vessel gets damaged. White blood cells destroy microorgan...
TD
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