Construct a flow chart exhibiting sequential events of oogenesis.

State ‘two’ observations made by German naturalist, Alexender von Humboldt during his extensive explorations in South American jungles.

OR

If in a population of size ‘N’ the birth rate is represented as ‘b’ and the death rate as ‘d’, the increase or decrease in ‘N’ during a unit time period ‘t’ will be:

The equation given above can also be represented as:

What does ‘r’ represent? Write any one significance of calculating ‘r’ for any population.

When and where do tapetum and synergids develop in flowering plants? Mention their functions.

OR

Where are the following structures present in a male gametophyte of an angiosperm? Mention the function of each one of them.

(a) Germ pore

(b) Sporopollenin

(c) Generative cell

Draw L.S. of an embryo of grass and label its parts.

OR

Draw a diagrammatic sectional view of a seminiferous tubule (enlarged) in humans and label its parts.

(a) How does mutation occur?

(b) Differentiate between point mutation and frameshift mutation.