Q: What kind of diseases can be difficult to treat because they live inside the host's cells, making it hard to destroy them without killing host cells? Choices: - superfluous diseases - nucleus diseases - cancerous diseases - viral diseases A:
viral diseases

Q: What does the placenta sustain during pregnancy? Choices: - the heart - the mother - the endocrine system - the fetus A:
the fetus

Q: How many chromosomes are in each set? Choices: - 22 - 21 - 13 - 23 A:
23