The main cause of psoriasis is:

Explanation: Psoriasis is believed to have a genetic component, and it is considered an autoimmune disorder where the immune system mistakenly attacks healthy skin cells, leading to the characteristic skin changes.

Incorrect choices: a. Poor hygiene and lack of skin care - Psoriasis is not caused by poor hygiene or lack of skin care.

b. Exposure to environmental toxins - While environmental factors may trigger or worsen psoriasis in some individuals, they are not the primary cause of the condition.

d. Excessive sun exposure - Sun exposure may improve psoriasis symptoms in some people, but it is not the underlying cause of the condition.

Explanation: Psoriasis is characterized by red and raised skin patches covered with silver or white scales. These patches are often itchy and can be found on various parts of the body, such as the scalp, elbows, knees, and lower back.

Incorrect choices: a. Clear and smooth skin without any changes is not consistent with psoriasis, which is marked by visible skin changes like red, raised patches.

c. Skin rash with fluid-filled blisters may indicate conditions such as contact dermatitis or eczema but is not typical of psoriasis.

d. Purple or red lumps under the skin are more suggestive of other conditions, such as nodules or hematomas, rather than psoriasis.