Identify the name of the reaction: $6CO_2 + 12H_2O \xrightarrow{\text{sunlight, chlorophyll}} C_6H_{12}O_6 + 6O_2 + 6H_2O$.

A unicellular animal $P$ having no fixed shape ingests a food particle by forming temporary finger-like projections $Q$. The food particle is engulfed with a little surrounding water to form a temporary stomach $R$ inside it. The chemicals $S$ from surrounding cytoplasm enter into $R$ and break down food into small and soluble molecules by chemical reactions. The digested food is absorbed directly into cytoplasm by the process $T$. The undigested food is thrown out of the body by the rupture of a cell membrane $U$ in a process called $V$.
$(a)$ Name the unicellular animal $P$.
$(b)$ What are $(i)$ $Q$, and (ii) $R$?
$(c)$ Name $(i)$ chemical $S$, and (ii) process $T$.
$(d)$ Name $(i)$ organelle $U$, and (ii) process $V$.

Name any two digestive enzymes secreted in the human digestive system and write their functions.

When carrying out the starch test on a leaf, why is it important to boil the leaf in alcohol?

$(a)$ Which enzyme initiates the digestion of proteins? Name the other enzyme produced by the same gland.
$(b)$ How would the digestion of proteins and carbohydrates be affected if the pancreatic duct is completely blocked?

Mention the major events during photosynthesis.