Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction.

Graves' disease is caused due to

Choose the correct statement.

The partial pressure of oxygen in the alveoli of the lungs is

Which hormones do stimulate the production of pancreatic juice and bicarbonate?

Match the stages of meiosis in Column-I to their characteristic features in Column-II and select the correct option using the codes given below :

Column-I Column-II

a. Pachytene (i) Pairing of homologous chromosomes

b. Metaphase I (ii) Terminalization of chiasmata -

c. Diakinesis (iii) Grossing-over takes place

d. Zygotenev (iV) Chromosomes align at equatorial plate