ACROSS
7. Carbon product obtained by pyrolysis
8. Communication via pen?
9. Big start of the 6-Down
10. Flower in the snapdragon family
11. Component of natural gas
13. Element in Einstein’s mass-energy equation
15. Musk ox and narwhal’s regional habitat
17. Lobes of a whale’s tail
18. Articulation involving the femur (2 wds.)
20. Sound off in a lupine fashion
22. Little songbird with a complex repertoire
23. Microscopic life forms
DOWN
1. Seed rich in omega-3 fatty acids
2. What a male seahorse can become, oddly
3. Bean with an Ethiopian origin
4. Network of vessels or nerves
5. Galliformes or Anseriformes members
6. Cosmologist’s allover concern
12. Period before the Quaternary, traditionally
14. The toxic stuff in poison ivy
16. What Jane Goodall studied
17. Unit important to oceanographers
19....