Answer:
cell membrane, DNA and RNA, cytoplasm, along with ribosomes
Explanation:
Answer:
Cells within a large multicellular organism communicate through chemical signals. These signals are relayed from one cell to another. A cell must have a receptor for that chemical to interpret and respond to a signal.
Explanation:
To initiate a physiological response, all body cells possess specific proteins known as receptors. These receptors are essential for detecting chemical signals and eliciting responses. Different receptors are tailored for various chemical signals; for instance, a dopamine receptor engages with dopamine molecules, whereas an insulin receptor specifically binds to insulin molecules. Additionally, certain cells may also respond to mechanical signals.
The hearts of birds and mammals, which have four chambers, are accurately classified as homoplasies. In evolutionary terms, homoplasies refer to traits that are shared across different species, even though their common ancestors lacked these traits entirely. To illustrate, both bird and bat wings perform a similar function of enabling flight, yet these structures evolved separately without being present in their ancestors. Consequently, while birds and mammals each have a four-chambered heart, their predecessors only possessed three chambers. This independent evolution exemplifies homoplasy.
