Answer: The endosymbiotic theory explains the Origin of the first prokaryotic cells
D. Origin of the first prokaryotic cells
Explanation:
Consentation? Or possibly freeze
Answer: B
Explanation: Traits usually die off when they are unneeded by the organism, or if the trait causes harm to the organism's survival. Through natural selection, over time, the organisms with the best combination of traits for its survival will become the dominating species, and those with weaker traits may not survive long enough to pass off their traits to future offspring.
Ans.
Human reproduction involves release of sperm (male gamete) and egg (female gamete) and their fusion to form zygote that develops into embryo. In females, an egg is released each month as a part of a monthly cylce, called menstrual cycle. The release of egg is termed as ovulation, in which tiny eggs are send into the fallopian tubes for fertilization.
Hence, the correct answer is 'a). an adult female usually releases an egg from an ovary each month.'
