Answer:
Something that indicates or fixes a limit or extent. Those two trees mark the boundary of our property. The mountain range that forms the country's northern boundary.
Explanation:
It is one of these meanings because I don't know what type of boundary you mean.
Most invertebrates leave their young to fend for themselves while vertebrates help their young till they are ready
The blisters occur in the second degree burn. The first degree burn only cause the damage to the outer layer of the skin. The blisters are a result of the accumulation of the fluid between the epidermis (outer layer of the skin) and the layers below it. So, for blisters to occur, at least damage to two layers of skin is necessary.
In first degree burn, due to the damage to epidermis only, the redness occur and the blisters does not occur.
The first three are the same as those found in DNA, but in RNA thymine is replaced by uracil as the base complementary to adenine. This base is also a pyrimidine and is very similar to thymine. Uracil is energetically less expensive to produce than thymine, which may account for its use in RNA.