Sewage holds toxic microbes and contains a mixture of suspended impurities. When these impurities hit drinking water microorganisms begin to deteriorate the water, and uses up the dissolved oxygen with the microorganisms, making these water dangerous to drink from. Major impacts of this can include giardia, salmonella, cryptosporidium, and E. coli.
There are about 950,000 species of insects known but estimates range as high as 2-10 million which means that there are probably many species not yet known which have probably gone undetected so far in perhaps more remote parts of the world.
Sponges have specialized cells and an endoskeleton, but they lack tissues and body symmetry. ... They include jellyfish and corals, both of which have radial symmetry. All cnidarians have nematocysts, and many are bioluminescent. They may exist in medusa and/or polyp form.
Answer:
B(sperm production)
D(appearance of secondary sex characteristics)
Explanation:
Answer:
Elements that are found in the same horizontal row (belong to the same period) in the periodic table, e.g. Fluorine and Neon both have the same energy level of 2.
<em>Note: The question does not specify any two elements.</em>
Explanation:
The modern periodic table is organized into eight vertical columns known as groups and seven horizontal rows known as periods. The atomic number ( number of protons in the nucleus) of elements increases when moving across the periodic table from left to right. The horizontal rows or periods represents an energy levels or the number of electron shells in an element. Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Elements belonging to the same period have the same number of energy level or shells. For example, the elements belonging to Period 2 include lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and neon. These all have the same number of energy level of 2.
