The cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were dominant forms during the age of the dinosaurs. though their sperm are flagellated, their ovules are pollinated by beetles. these beetles get nutrition (they eat pollen) and shelter from the microsporophylls. upon visiting megasporophylls, the beetles transfer pollen to the exposed ovules. in cycads, pollen cones and seed cones are borne on different plants. cycads synthesize neurotoxins, especially in the seeds, that are effective against most animals, including humans.
which feature of cycads distinguishes them from most other gymnosperms?
1. they have exposed ovules.
2. they have flagellated sperm.
3. they are pollinated by animals.
1 only
2 only
3 only
2 & 3
1, 2 & 3
Answers: 1
Biology, 22.06.2019 01:30
All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.
Answers: 1
Biology, 22.06.2019 04:20
Hybrid instruments that play sounds that are part sampled and part synthesized are known as:
Answers: 1
Biology, 22.06.2019 07:00
In 2001, records showed that local stocks of fish were down worldwide. yet, records of harvests indicated that fish were being taken at records rates. what was actually happening?
Answers: 3
Biology, 22.06.2019 11:20
2polnis which of the following is an advantage of an in vitro experiment?me
Answers: 1
The cycads, a mostly tropical phylum of gymnosperms, evolved about 300 million years ago and were do...
Mathematics, 10.02.2021 18:00
Mathematics, 10.02.2021 18:00
Mathematics, 10.02.2021 18:00
Biology, 10.02.2021 18:00
Chemistry, 10.02.2021 18:00
Mathematics, 10.02.2021 18:00
Mathematics, 10.02.2021 18:00
History, 10.02.2021 18:00
Mathematics, 10.02.2021 18:00