Q: Despite its small size, an erythrocyte contains about 250 million molecules of what? Choices: - calcium - plasma - potassium - hemoglobin A:
hemoglobin

Q: Bacterial contamination of foods can lead to digestive problems, an illness known as what? Choices: - acid reflux - headache - ulcers - food poisoning A:
food poisoning

Q: When vertebrate animals metabolize ammonia what is the primary byproduct that is produced? Choices: - carbon monoxide - dioxide - proteins - urea A:
urea

Q: What helps represent age-sex structure of the population? Choices: - habitat chart - density graph - biome model - population pyramid A:
population pyramid