a. Three features of the small intestine that increase the rate of absorption of digested food are:
1. Villi - finger-like projections on the lining of the small intestine that increase surface area for absorption.
2. Microvilli - smaller projections on the surface of the villi that further increase surface area.
3. Blood capillaries and lacteals - blood vessels and lymphatic vessels that absorb nutrients and transport them to other parts of the body.
b. Glucose formed in a plant during photosynthesis is used for energy or stored as starch for later use. The glucose is transported to different parts of the plant through the phloem tissue.
c. The mode of feeding in each of the following organisms are:
(i) Euglena - Euglena is a mixotrophic organism, meaning it can make its own food through photosynthesis or consume other organisms for nutrients through phagocytosis.
(ii) Spirogyra - Spirogyra is an autotrophic organism that produces its own food through photosynthesis.
d. Three characteristics of an Estuarine habitat are:
1. Salinity gradient - Estuaries are characterized by a gradient of salinity due to mixing of freshwater and saltwater.
2. High productivity - The high nutrient levels in estuaries support high rates of primary production.
3. Biodiversity - Estuaries are home to a diverse range of plant and animal species adapted to the changing environmental conditions.
e. Three differences between an aquatic habitat and a terrestrial habitat are:
1. Aquatic habitats are characterized by the presence of water, while terrestrial habitats are not.
2. Aquatic habitats have lower oxygen levels, while terrestrial habitats have higher oxygen levels.
3. Aquatic habitats have different temperature ranges and light levels compared to terrestrial habitats.