The outermost and innermost wall layers of microsporangium in an anther are respectively.

1. Endothecium and tapetum

2. Epidermis and endodermis

3. Epidermis and middle layer

4. Epidermis and tapetum

During microsporogenesis, meiosis occurs in

1. endothecium

2. microspore mother cells

3. microspore tetrads

4. pollen grains