Answer: It depends on if your only talking about plants if so the answer is coal.
Explanation: The reason being because coal only forms from the compaction of dead plants whereas petroleum forms from compacted plants and animals.
C. Sperm is produced in a male organism by meiosis
Los seres invertebrados y los vertebrados tienen más elementos en común de lo que se pensaba. Un estudio, con participación del Consejo Superior de Investigaciones Científicas (CSIC), prueba que existe gran similitud entre los sistemas excretores de ambos grupos de animales. Según la investigación, las células encargadas de filtrar la sangre en la formación de orina, alojadas en los riñones de vertebrados, son similares a las que realizan una función análoga en invertebrados.
Answer:
1. Signaling molecule
2. Signaling receptors
Explanation:
Hormones, growth factors, neurotransmitters, etc. serve the function of signaling molecules for cells. These molecules are released by one cell and bind to the receptors present on/in the target cells to elicit the desired response. Thereby, the signaling molecules serve in cell-cell communication.
For example, insulin hormone synthesized and released from beta cells of pancreas binds to its cell surface receptors present on the surfaces of liver cells and muscle cells to stimulate the uptake of the glucose from the blood.
Likewise, neurotransmitters released from the presynaptic neuron bind to receptors present on the membrane of postsynaptic neuron and serve to carry the nerve impulse to the postsynaptic neuron.
