In what general direction does mud creek flow?

Ectocarpene is a volatile, sperm cell-attracting material released by the eggs of the seaweed ectocarpus siliculosus. its constitution is all the double bonds are cis, and the absolute configuration of the chirality center is s. draw a stereochemically accurate representation of ectocarpene.

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

Select all the correct answers. for a claim about the natural world to be considered scientific, what attributes must it have? a).it must be applicable to future events and occurrences. b)it must be based on scientific observations that can be repeated in a controlled setting. c)it must be open to modification if new evidence doesn't completely support it. d)it must be consistent with only a small portion of relevant observations or data.