In the following situation, what happens to the rate of photosynthesis?
Cloudy days.

Why does absorption of digested food occur mainly in the small intestine?

The diagram below shows the human alimentary canal. $1$, $2$, $3$ and $4$ are four different organs that are parts of the canal.
$(i)$ Which of the labelled parts represents the liver?
(ii) Which of the following will be adversely affected in Mr. Ayub's body if his pancreas is malfunctioning, given that the pancreas secretes the lipase enzyme?

Stomata of desert plants remain closed during the day. Explain how and when they take up $CO_2$ to perform photosynthesis?

A student weighed some raisins and recorded the weight as $x$. She then soaked the raisins in distilled water. After about $2 \text{ hours}$, she removed the raisins, wiped them dry, and weighed them again, recording the weight as $y$. The percentage of water absorbed by the raisins can be determined using the relationship:

Name a unicellular animal which uses $cilia$ to move food particles into its mouth.