b) prop roots
mangrove trees grow near the water edges where the soil is wet and muddy. they are often subjected to waves and flooding. as a mean of extra support, they develop pitchfork like roots from the lower nodules in addition to the original root system. these are called prop roots which go down in the soil and anchor themselves. they branch further by trapping sediments in order to provide additional support.
a human genome is approximately 3 billion base pairs (represented by 4 letters each, a combination of a, c, g and t), so to represent all human genetic codes would require about 12 billion letters, for just one person.
b. looks, it's the only available answer that i can see working
blood is made up of red and white blood cells, platelets and plasma. the plasma consists of water (mostly) and dissolved nutrients. when blood is exposed to air, the blood will clot, due to aggravation of the platelets. then you get a forming scab that will heal the part that the blood is being exposed from.