Answer:
In biology, a gene is a basic unit of heredity and a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein. During gene expression, the DNA is first copied into RNA.
Euchromatin is a lightly packed form of chromatin that is enriched in genes, and is often under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic.
The genes present in heterochromatin are usually inactive. The genes present in euchromatin are either already active or will be active during growth. Heterochromatin is transcriptionally-inactive. Euchromatin is transcriptionally. (This one here is the difference)
Barometer is used to measure atmospheric pressure :)
The study of chemical reactions would be in chemistry and not biology so thats the answer
