Many individuals of the platyfish, Xiphophorus maculatus, have spots on their dorsal fins. A closely related species, the swordtail, X. helleri, lacks spots. In some backcross hybrids of these species, enlarged spots develop into malignant tumors, which reduce the organisms' life spans. This could be an example of .a. the Dobzhansky-Muller model of speciation.
b. beneficial hybridization.
c. the morphological species concept.
d. gene flow.
e. genetic compatibility.

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

What is the function of the somatic nervous system? connects the brain and the spinal cord to the rest of the body carry signals to the muscles and glands includes all nerves controlling the muscular system and external sensory receptors controls internal organs like the heart and bladder

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.