The multi-cellular haploid plant structure is called the gametophyte which is formed from the spore and gives rise to the haploid gametes
I think it's 420,000 kcal, because 10% of energy is lost as you move up each trophic level. To find what you started with you would multiply by 10 instead of dividing by 10. You have to multiply by 10 twice, because of the primary consumers and producers.
The answer is B
The big bang theory suggests that our universe formed approximately 13.7-13.8 billion years ago.