The correct answer is option a. true.
The fossil fuels, including coal and oil are present very deep inside the earth. In the carbon cycle, only fixation of atmospheric carbon dioxide in the organic material takes place. This cycle does not involve the recycling of the fossil fuels.
The burning of the fossil fuels directly release carbon dioxide and other carbon compound in the atmosphere, which was not involved in the cycle when it was present deep beneath the earth and ocean. Hence, the burning of fossil fuels increases the amount of carbon in the carbon cycle.
In his experiment mendel first crossed tall and short peas plant and noticed that the F1 plants were all tall. in the second experiment he crossed the the F1 plants and noticed that short plants reappeared in the rate of 25% in F2 generation. in his third experiment he crossed he crossed F2 plants and noticed that when he crossed some tall plants with the shot plants the F3 generation contained short plant in frequency of 50%. after this observations mendel concluded that there were genes that could be only expressed in homozygous state but not in heterozygous state. these genes were later referred to as recessive alleles wheres the genes that prevented the expression of recessive genes were later referred to as dominant genes.
