Why will this attempt at making multiple variables into one variable not work?

--each letter after "Blocker" is a Part.
a = script.Parent.Parent.Parent.Blocker.a
b = script.Parent.Parent.Parent.Blocker.b
c = script.Parent.Parent.Parent.Blocker.c
d = script.Parent.Parent.Parent.Blocker.d
e = script.Parent.Parent.Parent.Blocker.e
f = script.Parent.Parent.Parent.Blocker.f
g = script.Parent.Parent.Parent.Blocker.g
h = script.Parent.Parent.Parent.Blocker.h
i = script.Parent.Parent.Parent.Blocker.i
j = script.Parent.Parent.Parent.Blocker.j
blockers = {a,b,c,d,e,f,g,h,i,j}


function onClicked()
	blockers.Transparency = 0
	blockers.CanCollide = true
	
	end
	
			

script.Parent.ClickDetector.MouseClick:connect(onClicked)

In your code, blockers is a list.

A list does not have a Transparency property or CanCollide property, so modifying that would accomplish nothing.

Instead, you have to consider each element in the list:

for index, object in pairs( blockers ) do
	object.Transparency  = 0
	object.CanCollide = true
end

As DevFrank pointed out, the way you're defining blockers is unnecessarily long. You could instead just consider all of the Children of script.Parent.Parent.Parent.Blocker that are Parts.

So we change blockers to

blockers = script.Parent.Parent.Parent.Blocker:GetChildren()

but make sure each object IsA Part:

for index, object in pairs( blockers ) do
	if object:IsA("BasePart") then
		object.Transparency  = 0
		object.CanCollide = true
	end
end

If this "doesnt work", you should consult the output and provide that. Only so much help can be given when you give only a little information.

So when using ":GetChildren()" it creates a table of the children that you have decided to get from the object. Then when using for "for _,v in pairs(example:GetChildren) do" is a more sufficient way then doing, "for i = 1,#example:GetChildren() do". Then we must check if the object is a part in this case, which we use, :IsA("CLASSNAME") . Then after that I believe you understand already.

I will use a better way to do this in your situation.

script.Parent.ClickDetector.MouseClick:connect(function()
for _,v in pairs(script.Parent.Parent.Parent.Blocker:GetChildren()) do
if v:IsA("BasePart") then
v.Transparency = 0
v.CanCollide = true
end
end
end)

I also decided to use BasePart because I never knew it existed.

If you don't understand what I was trying to explain above, then let me post some links to the wiki. I did edit this because I felt that I wasn't telling you enough.

http://wiki.roblox.com/index.php?title=API:Class/Instance/GetChildren

http://wiki.roblox.com/index.php?title=Function_dump/Basic_functions#pairs

http://wiki.roblox.com/index.php?title=API:Class/BasePart

Don't forget to mark this as solved and as the correct answer!