Extract the original homework questions from the provided solution.

Here are the solutions to the questions:

21. The diagram below shows a phenomenon which occurs during cell division.

a) The stage of cell division in which this phenomenon occurs is Prophase I of meiosis.

b) The importance of the phenomenon taking place in the part labelled B (crossing over) is that it leads to genetic recombination or variation among offspring.

22. Name the region in plants where the following take place

a) Primary growth: Apical meristems (at the tips of roots and shoots).

b) Secondary growth: Lateral meristems (vascular cambium and cork cambium).

23. State three parameters that can be used to estimate growth in seedlings.

• Length or height
• Dry mass
• Number of leaves
• Surface area of leaves

24. State three reasons for classifying organism.

• To identify and name organisms systematically.
• To study the evolutionary relationships between different organisms.
• To organize and store information about organisms in a logical manner.
• To understand the biodiversity on Earth.

25. The diagram below represents a transverse section of an ovary from certain flower.

i) The structure labeled W is an ovule.

ii) The type of placentation illustrated in this diagram is axile placentation.