Questions

The art and science of map making is called Cartography.

The left atrium is the upper left chamber of the heart that receives blood from the pulmonary veins.

The heart is responsible for circulating blood throughout the body. The heart is divided into four chambers. The upper chamber is known as the atrium while the lower chamber is referred to as the ventricle.

Sad means being unhappy, sorrowful, mournful, wistful,...

Hence, Somber means cheerless i.e, unhappy which is synonym of sad. All other options are opposites of Sad.

Ganesha

Cretinism is a disease caused by hypothyroidism(less thyroxine formation).The symptoms of the disease are retardation  of mental, physical and sexual developments. Potbellt, protruding tongue, dry skin etc are also indicative of this disease.

The highly energetic gamma particles can penetrate most compounds that stop by other types of radiation. However, lead, steel, or concrete can reduce the high energy of these particles, making them less penetrating.

Hence, Gamma radiation can be stopped by a several inches of lead or steel, or several meters of concrete.