The relaxin secreted by placenta relaxes the public ligaments during parturition.
Mention any two other hormones secreted by placenta.

Name any two secretions of exocrine glands.

Placenta acts as an endocrine gland. Write any other two functions of placenta.

Human chorionic Gonadotropin (HCG) is a hormone produced during pregnancy. Identify two other hormones produced during pregnancy.

The chemistry of Boron is different from that of other members of the same group. Mention any two differences and give reason.

During the past century, the temperature of the earth has increased by 0.6% most of it during the last few decades. Rise in temperature causes serious changes in the environment, thus leading to increased melting of polar ice caps and other places like Himalayan snow caps. Suggest any two control measures that will reduce global warming.

The substance which can accept electrons is a Lewis acid. 'BCl_3, BF_3' and 'BBr_3' are Lewis acids. a. Arrange the above Lewis acids in the increasing,order of their acid strength. b. Give reason for this order of acidic strength, c. The chemistry of boron is different from that of other members of the same group. Mention any two differences and give reason.