Areading may appear to be different when viewed with one eye or the other, or when the head is moved from side to side or up and down. this apparent measurement difference is due to a change in position of the observer, and is called

a. extrapolation
b. interpolations
c. parallax

Answer : Parallax

Explanation :

The difference in the position of an object when viewed from different points is called Parallax.  

The principle of parallax is used by the astronomers to find the distance of a planet or a star from earth.

A baseline of 1 astronomical unit is used by astronomers to find the distance between the stars and the earth.  Also, they measured tiny angles in arcseconds.

By doing calculations they found the distance of a star from earth is about 93 million miles or 150 million kilometers.

So, the correct option is (C).

the plateau is likely to turn into a desert do to corrosion.

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂