Qualification > Sciences
Biology Paper 1
kam:
--- Quote from: sisler on June 05, 2009, 08:01:01 am ---hey ...
can anyone help me wid may/june2003 paper 1 - question 30 i dont understand how the answer is D
--- End quote ---
pollen grains are plants sex cells
so they have half
the answer is B
even in mark scheme
camel:
--- Quote from: kam on June 05, 2009, 08:04:01 am ---
--- Quote from: sisler on June 05, 2009, 08:01:01 am ---hey ...
can anyone help me wid may/june2003 paper 1 - question 30 i dont understand how the answer is D
--- End quote ---
pollen grains are plants sex cells
so they have half
the answer is B
even in mark scheme
--- End quote ---
nitrogen cycle??!?!!
247sports:
k nitrogen cycle very easy
first:
there is 79% of nitrogen in air which is inert i.e. doesnt react....but then some oragnisms need nitrogen to live so hw do they use it ??
this is done by the decomposers..turning nitrogen in a very usefull or in reactive form is calld nitrogrn fixation..
first lightin causes the nitrogen to react with oxygen to form its oxides..then they idssolve in rain and are washed into the soil where the decomposers convert it into nitarates or NH3....nw nitrogen-fixin bacteria they use nitorgen gas form the air n combine it with other sustances to make nitrtes n other usefull compounds...there is another bacteria who does teh opposite it converts the nitrates into nitrogen gas....its calld denitifyin bacteria...
n also these bacteria they breakdown the waate of naimal into nitarates too
phew anewho hope this helps n i think this is enuf for nitrogrn cycle
WHISH ME LUCK MY XAM IN 1 HR :s
Aodian:
LUCK ;D
Feva:
can someone explain transpiration ?
and the functoin on phloem?
Thank You
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