LUC Lurrect answer
1) Which of the following reaction is fast
a) 2g sodium carbonate + 1 M HCl aci
b) 2.5g Na, Co, + 1M HCl acid
c) 0.5g Na2CO3 +0.5M HCl acid
d) 2,5gNa2CO3 + 1MHCl at30c
2) Barium sulphate can be prepared by mixing
a) Barium carbonate and calcium salphate
B) Barium nitrate and lead sulphate
c) Barium Chloride and copper sulphate
d) Bao and Zinc sulphate
3) Which of the following elements can reduce Zinc oxide to Zn atom
a) Mg
c)Ag
b) Lead
d) Fe

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

you did not give any options thus this is the best answer i can give to you with this little information you have given

> they are both natural and not man made

> they can be tracked and predicted by the right tools

-love shrooms