Consider statements about environment: 1. The ozone layer is in the stratosphere. 2. CFCs deplete the ozone layer. 3. Global warming is caused by a decrease in CO2. Which are correct? MCQ with Answer and Explanation

Explanation:
James Watson and Francis Crick, using Rosalind Franklin's X-ray data, proposed the double helical structure of DNA in 1953.

Explanation:
Vitamin D (calciferol) promotes the absorption of calcium and phosphorus from the small intestine by inducing synthesis of calcium-binding proteins. It is synthesized in the skin upon exposure to UV light and then activated in the liver and kidneys. Deficiency leads to rickets in children and osteomalacia in adults. Vitamin A is for vision, C for collagen, B₁ for energy metabolism.

Explanation:
The 5' cap is a specially altered nucleotide (7-methylguanosine) attached via a 5'-5' triphosphate linkage to the 5' end of a eukaryotic mRNA molecule shortly after transcription begins. Its primary functions are to protect the nascent mRNA from degradation by 5' exonucleases, to facilitate the export of the mature mRNA from the nucleus to the cytoplasm, and, crucially, to be recognized by the eukaryotic initiation factor 4E (eIF4E), which is essential for recruiting the ribosome to the mRNA to initiate translation.