Nthe process of transcription, in the process of transcription, dna is replicated proteins are synthesized rna is synthesized mrna attaches to ribosomes

The answer is; RNA is synthesized

Transcription is the first  process of the central dogma where genes are turned into proteins. Transcription is mediated by RNA polymerase enzyme. The difference with DNA replication is that instead of the synthesized mRNA has Uracil in place of Thymine nucleotide. The RNA is also composed of ribose sugars instead of deoxyribose sugars.

"d.) carbon dioxide and hydrogen sulfide"