Explain with the help of diagrams the structrual differences between three types of cubic crystals.

(a) ''The pyramid of energy is always upright.' Explain. (b) Explain with the help of labelled diagrams, the difference between an upright pyramid of biomass and an inverted pyramid of biomass.

Diagrammatically show the difference between the three types of muscle fibres

With the help of a diagram, explain the structure of mature male gametophyte .

Explain a. The basic of sumilarities and differences between metallic and ionic crystals. b. Ionic solids are hard and brittle.

Explain oogenesis with the help of a neat labelled diagram