Answer:
Groundwater contamination occurs when man-made products such as gasoline, oil, road salts and chemicals get into the groundwater and cause it to become unsafe and unfit for human use. Materials from the land's surface can move through the soil and end up in the groundwater.
Answer: The endosymbiotic theory suggests that eukaryotic organisms evolve from primitive prokaryotic organisms.
Explanation:
According to the endosymbiotic theory the organelles like mitochondria and chloroplast in the eukaryotic cells have arisen from aerobic bacteria. The aerobic bacteria being prokaryotic cell was consumed by the anaerobic bacteria or prokaryotic cell.
The following are the evidences of the origin of eukaryotic organisms from prokaryotic organisms:
1. The chloroplast and mitochondria have circular DNA like bacteria.
2. The mitochondria and chloroplast reproduce through binary fission which also occurs in bacteria.
Answer:
False
Explanation:
Cytosine, guanine, thymine, and adenine are collectively referred to as nitrogenous bases. These are not phosphates. The cytosine, guanine, thymine, and adenine are the four different types of nitrogenous bases. These nitrogenous bases are present in the deoxyribonucleotides. Cytosine and thymine are smaller in structure and have single ring structures. These are collectively called pyrimidines. On the other hand, adenine and guanine are the larger nitrogenous bases each with double ring structures. They are collectively called purines
Isotopes are variants of a particular chemical element which differ in neutron number, although all isotopes of a given element have the same number of protons in each atom. The term isotope is formed from the Greek roots isos and topos, meaning "the same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same position on the periodic table.
This might be wrong and i am sorry if it wrong but i think it is A. a planet that produced flowers and seeds on tall stalks and i am sorry again if its wrong
