Which part of the brain is associated with conscious thought

Cerebral cortex of the Cerebrum

Explanation:

The body directs our body's internal functions. These functions are made possible by four major regions of the brain viz: The Cerebrum, Diencephalon, Cerebellum and Brain stem.

The Cerebrum is the largest brain structure, making up most of the total brain, and a part of the forebrain. The cerebrum's prominent outer portion, the cerebral cortex, not only processes sensory and motor information but also enables CONSCIOUSNESS (our ability to consider ourselves and the outside world), thoughts, emotion, reasoning and memory.

The cerebral cortex is composed of the right and left hemispheres joined by the corpus callosum. Each cerebral hemisphere can be subdivided into four lobes (Frontal, Parietal, Temporal, and Occipital) associated with different functions.

"d.) carbon dioxide and hydrogen sulfide"