What are the factors needed for maintaining the direction of diffusion in plants?

In which part of the digestive system is water absorbed?

Which of the following statement$(s)$ is (are) true about respiration?
$(i)$ During inhalation,ribs move inward and diaphragm is raised
$(ii)$ In the alveoli,exchange of gases takes place i.e.,oxygen from alveolar air diffuses into blood and carbon dioxide from blood into alveolar air
$(iii)$ Haemoglobin has greater affinity for carbon dioxide than oxygen
$(iv)$ Alveoli increase surface area for exchange of gases

Why is transpiration important for plants?

What will happen if:
$(a)$ Peristaltic movements do not occur all along the oesophagus?
$(b)$ There are no platelets in the blood?
$(c)$ Rings of cartilage are not present in the trachea?

Describe the process of urine formation in kidneys.