Q: What is the combination of tissues that provides a tough, woody external covering on the stems of trees called? Choices: - cuticle - scale - epidermis - bark A:
bark

Q: What drives puberty in male humans? Choices: - bloodstream - estrogen - methane - testosterone A:
testosterone

Q: Q: What substance comes toward earth's crust through mantle plumes? Choices: - rocks - water - gas - magma A:
A: magma

Question: Q: Sounds, chemicals, and visual cues are examples of what between animals? Choices: - migration - circulation - procreation - communication A:
Answer: communication

*Question*
Q: Phosphorus exists as several allotropes, the most common being red, black, and what? Choices: - purple phosphorus - yellow phosphorous - green phosphorus - white phosphorus A:
**Answer**
white phosphorus

*Question*
Q: An antigen is a molecule that reacts with some component of the what response? Choices: - digestion - fight or flight - hormones - immune A:
**Answer**
immune