You would weigh less on Mars than on Earth because there's less gravity on Mars
Answer:
About composition of water and organisms that lives there.
Explanation:
scientists might be able to learn about the composition of seawater that was present millions of years ago if we study those stones that comes in contact to that ancient seawater because the traces of particles still present on it. This study provides valuable information about ancient times of earth and its natural resources. These rocks also provides animals that were present in that sea water at that time.
Because an antibody is "made" relative to the antigen, but kept at low levels when you are exposed the first time ("primary immune response"). The second time you're exposed to the same antigen, memory cells recognize it and the body produces a high level of antibodies, and the level of antibodies usually remains higher for a longer time ("secondary immune response"). This is your basic immune response (primary and secondary).
This explains exactly why vaccines are effective to extremely effective.