Questions

The absence of a nucleus is an adaptation of the red blood cell for its role. It allows the red bloodcell to contain more haemoglobin and, therefore, carry more oxygen moleculesLike red cells, platelets (thrombocytes) have no nucleus.Monocytes have a small spherical nucleus and has abundant dark staining condensed chromatin.There are 5 organelles found in a root hair cell. They are the: nucleus, cytoplasm, cell membrane, cell wall and vacuole.

Alluvial Soils

The proportion of nitrogen is generally low, but potash, phosphoric acid and alkalis are adequate, while iron oxide and lime vary within a wide range.

Black Soils

Chemically, the black soils are rich in lime, iron, magnesia and alumina. They also contain potash. But they lack in phosphorus, nitrogen and organic matter.

Laterite Soils

With rain, lime and silica are leached away, and soils rich in iron oxide and aluminium compound are left behind.