Consider the following statements about the human heart: 1. The right atrium receives blood from the vena cavae. 2. The left ventricle pumps blood to the lungs. 3. The septum separates the left and right sides. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
In C4 plants, the initial fixation of CO2 occurs in the mesophyll cells. The primary CO2 acceptor is a 3-carbon compound, phosphoenolpyruvate (PEP). The enzyme PEP carboxylase catalyzes the reaction, forming a 4-carbon compound, oxaloacetate (OAA). In C3 plants, the primary acceptor is RuBP, a 5-carbon compound, and the enzyme is RuBisCO.

Explanation:
Transpiration from stomata creates negative water potential in leaves, generating a tension (transpiration pull) that draws water upward through the xylem from roots. This cohesion-tension mechanism is the primary driver of water transport in tall trees. Root pressure and capillary action are minor forces.

Explanation:
Thyroid Stimulating Hormone (TSH), also known as thyrotropin, is a glycoprotein hormone secreted by the thyrotroph cells of the anterior pituitary gland. Its primary and specific target is the thyroid gland. TSH binds to receptors on the thyroid follicular cells, stimulating all aspects of their function: the uptake of iodine, the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3), and the release of these hormones into the bloodstream. TSH secretion is regulated by Thyrotropin-Releasing Hormone (TRH) from the hypothalamus and by negative feedback from T3 and T4.