What represents the structure of kelp from top to bottom? ( SCIENCE ) 1. holdfast, blade, gas bladder

2. gas bladder, holdfast, stipe

3. blade, gas bladder, holdfast

Which of the following sex and generation combinations directly produces the pollen tube of angiosperms? a) male gametophyteb) female gametophytec) male sporophyted) female sporophyte

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

The human genome project is devoted to mapping the general dna sequence of our species. this could lead to the development of new medicines, as well as the possibility of using gene therapy to treat certain diseases. however, there are some ethical issues surrounding the mapping of individual genomes. one concern is a) that your genes may change over time, making the project useless. b) that insurance companies could discriminate based on genetic make-up. c) that since this has never been done before, we should probably not do it now. d) that sequencing our individual genomes is so expensive, it is a counter-productive strategy.