Water quality tests from a local river show low levels of a single heavy metal. The level of heavy metal in the water is under the acceptable legal limit and does not affect the local population's drinking water. The residents of the next town, down river from the first town, are suffering from numerous stomach ailments and are showing signs of long-term kidney damage. Water quality tests in the river by the second town show two types of heavy metals in the water. One of the metals is the same as the metal in the first town. What can scientists infer about the possible reason for the illnesses in the second town? More metals cause acute effects but not chronic effects. The first metal causes an acute effect compared to the other. The heavy metals have a synergistic relationship when combined. The heavy metals have an antagonistic relationship when combined.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.