Prior to the industrial era, pre 1780 affected earth climate because they emitter both aerosols and carbon dioxide into the atmosphere

a) sunspots
b) volcanoes
c) fossil fuels
d) meteorite impacts

B. volcanoes

Explanation: Prior to the industrial era, volcanoes affected earth climate because they emitted both aerosols and carbon dioxide, sulfur dioxide into the atmosphere.When volcanic eruption take place they eject lava, sulfur dioxide, carbon dioxide, silica, ash, molten rock and dust. These gases makes the environment very dusty and polluted. These volcanic gases stays in atmosphere forever and affect the climate.

  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