Which of the three fundamental tissues have a secondary cell well? (Parenchyma, collenchyma and sclerenchyma)

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?

If a human has 23 pairs of chromosomes in every muscle cell of its body how many chromosomes will be in a human egg or sperm