Ascariasis is a common helminthic disease caused by: MCQ with Answer and Explanation

Explanation:
In C4 plants like maize and sugarcane, CO₂ is initially fixed in mesophyll cells by PEP carboxylase, producing a four-carbon compound oxaloacetic acid (OAA), which is then converted to malate or aspartate and transported to bundle sheath cells. Here, CO₂ is released and enters the Calvin cycle. This adaptation minimizes photorespiration.

Explanation:
Beta cells of the islets of Langerhans secrete insulin, which lowers blood glucose. Alpha cells secrete glucagon (raises glucose), delta cells somatostatin, and acinar cells produce digestive enzymes.

Explanation:
The respiratory system, primarily the lungs, facilitates the exchange of gases (oxygen and carbon dioxide) between the blood and the external environment. The circulatory system, centered around the heart and blood vessels, transports blood containing oxygen, nutrients, hormones, and waste products throughout the body. The excretory system, primarily the kidneys, filters blood to remove metabolic waste products and excess water, excreting them as urine. All statements are correct.