Question

1. which set of descriptions is correct

1 point
(images of energy graphs for reactions)
option 1: photosynthesis, endothermic and has the following energy graph
option 2: cellular respiration, exothermic and has the following graph
option 3: cellular respiration, endothermic and has the following graph
option 4: photosynthesis, endothermic and has the following graph

Explanation:

Step1: Analyze reaction types

Endothermic reactions absorb energy (products have higher energy, $\Delta H>0$), exothermic release energy (products have lower energy, $\Delta H<0$). Photosynthesis is endothermic (uses light energy), cellular respiration is exothermic (releases energy).

Step2: Analyze energy graphs

• Top - left graph: Reactants have higher energy than products (exothermic - like cellular respiration? No, wait: Wait, no—wait, photosynthesis is endothermic (needs energy, so products (glucose) have more energy than reactants (CO₂, H₂O)? Wait, no: Wait, potential energy in graphs: For endothermic, products have higher energy ($\Delta H>0$). For exothermic, products have lower energy ($\Delta H<0$).

Wait, let's re - check:

Photosynthesis: $6CO_2 + 6H_2O + energy
ightarrow C_6H_{12}O_6 + 6O_2$ (endothermic, $\Delta H>0$, products have higher energy than reactants).

Cellular respiration: $C_6H_{12}O_6 + 6O_2
ightarrow 6CO_2 + 6H_2O + energy$ (exothermic, $\Delta H<0$, products have lower energy than reactants).

Now, look at the options:

Option 1 (top - left graph description): Says photosynthesis, endothermic. But the top - left graph has reactants (higher) than products (lower) → exothermic. So wrong.

Option 2 (top - right graph): Says cellular respiration (exothermic) but the graph has $\Delta H>0$ (endothermic, products higher). Wrong.

Option 3: Cellular respiration (exothermic process) described as endothermic. Wrong.

Option 4: Photosynthesis (endothermic, $\Delta H>0$, products have higher energy than reactants) and the graph (assuming the bottom - right graph has $\Delta H>0$) matches. So this is correct.

Answer:

The option "photosynthesis, endothermic and has the following graph" (the bottom - right option) is correct.