In the phrase "Carthago delenda est" what is the case and construction of "delenda"?
Here, "delenda" is a nominative form of the future passive participle. It is being used in a passive periphrastic, so the phrase is translated "Carthage must be destroyed".
I'm having trouble learning vocabulary for a foreign language. What should I do?
First, write out the vocabulary list by hand. Studies have shown that physically writing out lessons improves retention. then you can make flashcards (irl or online) and practice a bit everyday. Try drawing pictures on the cards to help you make associations to remember the words. For example, my friend was trying to remember that in Latin "copia" means abundance, so she drew a picture of a dancing cinnamon bun.
David and Rose have one child, and want another. Rose is a carrier for Hemophilia, an X-linked recessive trait, and John does not have the disease. If their child is male, what is the likelihood that it will have the disease? If it's female?
In either case, there is a 50% chance that the child will inherit an X chromosome with the recessive allele for hemophilia from Rose. If the child is a girl, however, she will always have a dominant allele from David, so she will not inherit the disease. A male child must inherit David's Y chromosome. Thus, if it is a boy, the child will have a 50% chance of inheriting the disease, because he has only one X chromosome.