Badges: 13
Report Thread starter 1 year ago
Here's a link to the question:

Q3 parts ii and iii

Here's the mark scheme:

I don't understand why in part ii, they mention CO2 in the mark scheme when CO2 isn't produced in anaerobic respiration,

For part iii
I don't understand what they expect me to say, I genuinely don't
The first and probably only thought that came to my head when I first read the question was : Because this is an animal and this is a seed, they have different metabolic rates, they have different rates of respiration, they need different amounts of energy.

But ofc the mark scheme had better answers, none of which I understand, forget the first marking point but can someone please help me in the rest ?
Badges: 12
Report 1 year ago

I got a little confused as to what the mark scheme had intended to imply in part (ii) at first, but I think I got it. Basically, the soda lime is there to absorb the carbon dioxide in order to prevent the inaccurate readings of the liquid moving that may be resulted. So the carbon dioxide produced being absorbed has nothing to do with anaerobic respiration, it just wants you to mention that there is no gas, like carbon dioxide, that may change the movement of the liquid part. To be honest, it's confusing as hell, and I probably would've done the same mistake. It's two marks, and saying anaerobic respiration and lack of oxygen production, as well as the fact that the liquid drop would not move due to the lack of gas present, would be enough.

For the part (iii), obviously one of the main facts is the fact that they have a drastic difference in their dry mass, meaning that the insects have to supply more energy, but you already know that.

As for the rest, I'm just as confused as you. The only thing I can come up with is the fact that both insects and seeds rely on their environment for heat, which is a factor that helps increase the rate of respiration. To make it more accurate, you should make sure both of them have the same temperatures. Honestly, I have no idea about the third marking point, your board looks super difficult. I'm sorry I couldn't help that much.

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