In savanna trees, thick corky bark is an adaption for

Step 1: Analyze the question The question asks what function thick corky bark serves in savanna trees. Savanna regions have a long dry season, and bush fires are common, especially during harmattan.

Step 2: Explain the concept Cork cells are dead cells with walls impregnated with suberin, a waxy substance. This makes cork:

• Thick and insulating, so it protects the inner living tissues (cambium and phloem) from heat.
• Poorly flammable and able to resist burning.
• Waterproof, though this is a secondary benefit.

Savanna trees such as the locust bean tree (Parkia biglobosa) and shea butter tree survive the yearly bush fires because of this thick bark.

Step 3: Evaluate the options

• A. Absorbing water: roots do this, not bark. ✗
• B. Conserving water: cork does reduce water loss slightly, but this is not the main adaptation of thick bark in the savanna. Leaf adaptations, such as small or waxy leaves, do this. ✗
• C. Enhancing transpiration: the opposite of what a dry habitat requires. ✗
• D. Reducing transpiration: most transpiration happens through the leaves, so this is mainly a leaf adaptation. ✗
• E. Resistance to bush fire: this is the specific, classic reason for thick corky bark in savanna trees. ✓

Step 4: Answer The correct option is E, resistance to bush fire.

Tip: Link the habitat to its dominant hazard. In the savanna the hazard is fire, so think "thick bark = fire protection". In the desert the hazard is water loss, so think "reduced leaves, waxy cuticles, sunken stomata".