I think that correct answers are: <span>Some of them lose their leaves in winter. (i.e. <span><em>Larix</em></span>)</span> <span>They include the tallest plants (i.e<em>.Sequoia)
</em>I don't think they are the oldest type of seed plants, since in the past the classes like progymnosperms and seed ferns existed prior to the gymnosperms. But question isn't absolutely clear to me and I can't be 100% sure. All of the gymnosperms have seeds unless human grows some seedless variant. Gymnosperms don't have flowers like angiosperms do, but some people think that cone is kind of flower. Male cones produce pollen, not female. Hope I helped :) <em /></span>
In some parts of Africa, up to 20% of the population are carriers of the sickle cell gene. This suggests that the trait must have a survival value. The carriers of the trait have a much lower susceptibility to malaria than normal individuals. This is because the malaria parasite survives very poorly in sickled red blood cells.
