Why is the a shell considered to be biotic

What are some possible short and long term medical concerns for crew members on longer space exploration trips

Based on the number of offspring they produce at one time organisms are classified into two categories many offspring at once and a few at a time sort the carry sticks based on the category they describe

Which one is an advantage of external fertilization a. the offspring are genetically identical to the parents b. more eggs can be fertilzed at one time c. more sperm can be released at one time d. more protection is available for developing plz