The theory is the Continental drift, the super-continent is called the Pangaea.
A. A gamete carries to genes for a trait.
B. A gamete carries one allele for a gene.
C. A gamete can carry multiple alleles for a trait.
D. Some gametes are dominant and some are recessive.
It depends on which virus you are referring to specifically. Viruses come in many shapes and types; their variations are tremendous.
For HIV and Influenza, viruses acquire their envelops after maturation, during the budding off or detachment stage from the host cell.
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Scratching insect bites can lead to infection, a superficial crusty infection of the skin.The scratching cause the skin around the bitten area to break open which causes infection. Example of insect that bites are mosquito, midge and flea among others.