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how is crude oil seperated into different fractions
- the crude oil is heated to vapourise the mixture
- the oil then cools and condenses at its boiling point
- different fractions have different boiling points , so condense at different temperatures so can be collected seperately
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Joshua trees live in deserts . Joshua trees have two types of root . they have a system of shallow roots spread out over a large area and they have roots about 1 m in diameter , shaped like bulbs deep in the soil explain the advantage of a Joshua tree having
shallow roots spread out over a large area
it will be able to get watwe from a large area after rain
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Joshua trees live in deserts . Joshua trees have two types of root . they have a system of shallow roots spread out over a large area and they have roots about 1 m in diameter , shaped like bulbs deep in the soil explain the advantage of a Joshua tree having
large , bulb like roots deep in the soil
it will stabalize the plant in thr ground
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creosote bushes also live in deserts the leaves of creosote bushes are covered with a layer of wax and fold together during the day
explain how the leaves of the creosote bush help it to survive in deserts
they reduce water loss , the wax will refelect heat and the folding reduces the surface area
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name two hormones used in IVF
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describe IVF
FSH and LH are given to the woman before egg collection to stimulate egg production ggs are collected from the womens ovaries and fertilised in a lab using the males sperm . These are the grown into embryos, once the embryo's are tiny balls of cells , one or two of them are then inserted into the womens uterus to improve the chance of pregnancy
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what are the pros and cons of IVF
- pros = fertility treatment can give an infertile couple a child
- Cons = some women have a strong reaction to the hormones (abdominal pain , vomiting , dehydration)
- Cons = there have been som reports of an increase risk of cancer due to the hormone treatment
- Cons = multiple births can happen if more than one embryo grows into a baby - these are risky for the mother and baby (there's a higher risk of miscarrage , stillbirth)
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give one advantage in any research project , of having a large sample size rather than a small sample size
there is enough data to indicate relationships
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explain how teh spectrum shift of the dark line supports that theory that the universe bgan from a small initial point
- the light has been shifted to the red end of the spectrum
- the wavelength increases
- suggesting that galaxies are moving away from each other
- suggesting the universe is expanding outwards from a single point
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why does a liwuid cool down when it evapourates
- there are attractive forces between molecules
- only the fastest molecules have enough energy to break away from the other molecules
- the molecules escape from the surface of the liquid
- the average speed of the molecules decreases
- the lower the average speed of the molecules the lower the energy and the lower the temperature of the liquid
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