Biologists think that endosymbiosis gave rise to mitochondria before plastids partly because: (All eukaryotes have mitochondria whereas many eukaryotes do not have plastids)
Answer:
about 5 billion years ago
Explanation:
Our solar system formed about 5 billion years a go from a dense cloud of interstellar gas and dust.
positive feedback could be contractions(as painful as it may seem, its true) in child birth and the ripening of fruit.
negative feedback include the regulation of blood glucose levels and osmoregulation
Answer:
Helium
Explanation:
Helium is extracted in a few places in the world, namely USA, Algeria, Russia and Qatar. Helium is abundant in space, where it's produced as a product of the fusion reaction inside stars such as the sun.
Chromosome is to cactus as gene is to a needle.
