Please can someone explain. I thought photosynthesis (plant nutrition) absorbs carbon dioxide and gives off oxygen. Why respiration?
I think you're confusing it. Look it says which process leads DIRECTLY to the exchange of gases indicated. During the night, plants don't make oxygen from photosynthesis so they have to absorb it. And since they aren't photosynthesising, they release it carbon dioxide directly. During the part of the day with bright sunlight, the oxygen is still produced but its actually a lot more than necessary and released. Carbon dioxide is also made but its a lot less. So the plant has to absorb it from the surroundings...
Secondly, in that question about seeds, its wind for seed 2 cause look at it. They have a large surface area to increase air resistance..
and the other is mammal for attaching to it (I've never seen birds with seeds on em
.)
Thirdly, that question about the leaf, alcohol (common reference to ethanol) is B. Just recall the process of testing a leaf for starch. First, its boiled to make it permeable, then heated with ethanol (using a water bath since ethanol is flammable) to dissolve chlorophyll then washed with water then iodine is added...