Literature Bai Chun stopped smiling, and his expression became serious. With a skeptical attitude and gaze, he looked at Bai Lan.

Bai Lan noticed that Bai Chun's gaze at her was a little wrong, so she asked, "What are you doing?" What do you want? ”

Bai Chun: "I ask you, what do you mean by oviparous?" ”

Bai Lan thought for a few seconds, and then replied: "Oviparous, that is, the sperm of an animal is hatched outside the mother's body and develops into a new individual...... Colonization. ”

Bai Chun asked again: "So, what is viviparity?" ”

"Viviparous? Hmm......" Bai Lan tilted her head slightly, thinking quietly for a moment, and then said, "Viviparity is the child of what egg is in the body of a female animal...... The process of maturation in utero and then production out. ”

Bai Chun: "What kind of animal is a viviparous animal in general?" ”

"I know!" Bai Lan's little face was slightly red, and she immediately responded, "Feed the Fu Animal!" ”

Bai Chun: "Let me ask you: how do viviparous animals get nutrients and how do they survive when they are just born?" ”

Bai Lan said: "How to survive? By eating, of course...... Milked. ”

"Whose milk?" Bai Chun asked.

Bai Lan: "Hmm...... Mother's milk. ”

"Very well," Bai Chun added...... "then, how do you get nutrients when the viviparous animal is not born from the womb?" ”

Bai Lan replied: "Through the umbilical cord and placenta, nutrients are obtained from the mother. ”

Bai Chun said: "About 45 million years ago, there were modern feeding animals on the earth...... About 63 million years ago, placental feeders appeared on Earth. I ask you: What about before that? ”

Bai Lan thought for a moment, and then said tentatively, "Dinosaurs? The age of the dinosaurs? ”

"Yes," Bai Chun said, "before the Fufu animals, the main animal on the earth was a class of reptiles that evolved from amphibians. The typical representative of this type of animal is the dinosaur. ”

Bai Chun said again: "Bai Lan, let me ask you: Are dinosaurs oviparous or viviparous?" ”

Bai Lan: "Oviparous, of course!" ”

Bai Chun: "So, oviparous animals appear first on the earth, and then ......"

"Viviparous animals appear!" Bai Lan said.

Bai Chun: "So, oviparous animals first appeared on the earth, and then viviparous animals gradually evolved. As I mentioned earlier, viviparous animals are generally feeding animals. Conversely, it is also true that feeding animals are generally viviparous. ”

Bai Lan: "What about the general situation?" ”

"Hmm......" Bai Chun was thinking about the problem.

"There it is!" After thinking for a while, Bai Chun told Bai Lan, "For example, the only peculiar toad in the world that does not lay eggs: the African viviparous toad. Another example is the platypus and echidna, which are oviparous and echidnus, although they are feeders. ”

"Whew......" Bai Lan exhaled unconvinced, and then said, "But what...... Does what you say have anything to do with explaining viviparity and oviparity, which mode of reproduction has a higher survival rate for offspring? ”

"Of course it does!" Bai Chun said.

"Oh?" Bai Lan pretended to be puzzled and said, "Tell me about it." ”

"Little Bailan, listen up."

Bai Chun said:

"Oviparity and viviparity were explained separately, and we know that viviparity evolves after oviparity. In addition, viviparous animals are generally also feeding animals.

Viviparity and feeding greatly improve the survival rate of offspring. Viviparity provides protection, nutrition and stable thermostatic development conditions for the developing embryo, which can ensure the normal progress of enzyme activities and metabolic activities, and can minimize the adverse effects of external environmental conditions on embryonic development. In addition, the amniotic fluid in the uterus can reduce the impact of vibration on the fetus.

However, the embryos of oviparous animals are not so lucky. The offspring of oviparous animals are in an egg that can be easily stolen or destroyed by other animals before they are born. In addition, the existence and hatching of eggs of oviparous animals basically have special requirements for the external environment, such as temperature, moisture, light, and so on. ”

"Okay......" Bai Chun finally said to her, "Little Bailan, do you understand?" As he spoke, he stretched out his hand, wanting to do something bad to her.

"Don't move!" Bai Lan shouted, dodged her body in an instant, and hid to the side, her dark eyes glared at someone, and she screamed, "Don't touch me!" ”

Bai Chun asked, "What are you yelling about?" Am I going to ...... Hit you? ”

"Hmph......" Bai Lan's cheeks were slightly pink, and she said unhappily, "You are so bad." Don't think I don't know, you're trying to flick my forehead with your fingers again......"

"Is there one?" Bai Chun looked innocent, showed a simple and pure smile, and said, "Do I look like that kind of person?" ”

Bai Lan: "Of course you have, of course you are!" ”

"Okay," Bai Chun said, "I have, I am." Okay, right? ”

Bai Lan smiled slightly. She's a little smug.

Bai Chun asked her, "Do you have any other questions?" ”

Bai Lan waved her hand and said pretending to be grand: "No, no." ”

"Alas......" Bai Chun pretended to be very sorry, and said to her with a straight look, "Since that's the case, then don't come to ask me questions in the future." ”

"Is this true?" Bai Lan couldn't wait to ask, "Why?" ”

"Of course it's true," Bai Chun said unceremoniously, "Anyway, don't ask me questions in the future." ”

"Wow......" Bai Lan pretended to cry without tears, and said sadly, "Is it so ruthless?" I'm your sister......"

Seeing her like this, Bai Chun's heart felt something. He sighed humbly and said regretfully, "Uh...... All right...... In that case, don't bother me this week. ”

Bai Lan: "This week? ”

Bai Chun: "What? You think time is too short, do you? ”

"No, no," Bai Lan sighed repeatedly, "No! ”

Bai Chun looked at her screaming, showed a pleasant smile, and said, "What are you 'no' or 'no'?" Do you want to kill me? ”

"No, it's not ......" Bai Lan hurriedly defended, but thought in her heart: You are a big bad person, if only I could kill you.

Bai Chun asked knowingly: "Why is that?" ”

Bai Lan blinked cutely and whispered, "Brother, can you shorten this time a little." ”

Bai Chun: "Why?" ”

"After all......," said Bai Lan, "people love to talk to you about their studies." ”

Bai Chun: "Okay. You let me think about it first......"

"Hmm......" Bai Lan looked at Bai Chun seriously with wide black eyes, her eyes were clear and clear, she actually made a strange moan, "Huh......"

Crackling! In an instant, Bai Chun felt that he had been struck by lightning from nowhere.

After a while......

Bai Chun asked, "Three days." What do you think of three days? ”

Bai Lan: "No, no! ”

The corners of Bai Chun's mouth curled slightly, looked at her, and said, "Then, two days...... Two days, how's that? ”

"No," said Bai Lan dissatisfied, "no! ”

Bai Chun looked at her in surprise and said, "That's good, one day, just one day." What do you think? ”

"No," Bai Lan cried out dissatisfied, shaking her pretty head, "really not! ”

Bang! Bai Chun immediately stood up from his chair.

Bai Lan immediately took three steps and jumped twice, and ran away. She hid in a corner, looking at Bai Chun tremblingly, with a pitiful appearance, she asked Bai Chun, "What are you doing?" What do you want? Boom...... Big Bad Dan ......"

Bai Chun wants to do it now, really wants to...... Why doesn't a whip appear in my hand? He gritted his white teeth, and thought maliciously in his heart: I really want to use a small leather whip to teach this little girl who doesn't know the height of the sky...... Thief.

Bai Chun stared at Bai Lan, who was acting. His eyes were already faintly erupting with flames of rage. Obviously, Bai Chun was angry. Seem...... Very angry.

Bai Lan realized that something was wrong. She exclaimed, "Oops, dangerous! The volcano is about to erupt! Big Bad Dan is going to bully the little girl, run! In an instant, Bai Lan took a thousand steps outward.

As soon as the smoke slipped away, Bai Lan soon ran away.

Bai Chun looked at the empty doorway, stunned. Long......

(End of chapter)

Degree of literature

Degree of literature