Tutor profile: Ann D.

Give two similarities and two differences between a subduction zone and a collision zone.

A subduction zone and collision zone both occur when two plates move together or converge towards each other. Earthquakes can occur in both zones due to build up of pressure and friction between plates. A subduction zone occurs when two oceanic plates or a continental and oceanic plate converge. A trench is formed as the heavier plate subducts beneath the lighter plate. This leads to the melting of the crust which in turn leads to volcanoes forming on the lighter plate. In a collision zone, on the other hand, two continental plates meet. There are also no volcanoes or trenches as no crust is subducted.

Explain, with the aid of an example, a pro-natalist approach in demography.

A pro-natalist approach seeks to increase the population of a country by increasing birth rates. This is done by using strategies such as marketing campaigns and by providing various incentives to the population to encourage them to have children. One example of this, is in Russia where birth rates are low and death rates are high, leading to negative natural increase. Women are more focused on following their career paths and are having children at a later age. If they do have children they may only have one. Incentives have been provided by the Russian government such as cash payouts and mortage susbidies for low income families.

Simplify the following algebraic fraction expression: $(\frac{x^2+4x\ -5}{x\ -1}+\ \frac{x^2-1}{x+1}$)

Step 1: Factorise both fractions. The numerator in the first fraction is a quadratic or trinomial. The numerator in the second fraction is a difference of squares. $(\frac{\left(x\ +\ 5\right)\left(x-1\right)}{x\ -1}+\ \frac{\left(x+1\right)\left(x-1\right)}{x+1}$) Step 2: Simplify both fractions. In the first fraction common factors of x-1 in numerator and denominator become 1 and 'cancel' out. In the second fraction common factors of x+1 in numerator and deonominator become 1 and 'cancel out'. $(\begin{array}{l}\left(x+5\right)+\left(x-1\right)\\\end{array}$) Step 3: Add and subtract like terms $(\left(x\ +\ 5\right)+\left(x-1\right)\ =\ 2x\ +4$)