Khẳng định nào sau đây đúng?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 23 to 30.

     Animals are primed to be wary through natural selection rather than scary television shows, but like humans, they often make mistakes when watching out for threats.

     Identifying stealthy predators is already a difficult task. From the perspective of a songbird, a harmless crow flying overhead may look similar to a raptor. But predator identification is made more challenging by the fact that prey animals often juggle multiple activities like foraging, keeping an eye on competitors and courting mates, all at the same time.

     This can be made easier by working as a group. Members of a school of fish, flock of birds or herd of antelope can share the task of watching out for predators. When an animal detects a predator, they share this information with other group members directly, by producing a warning, or inadvertently, by preparing to flee. The group as a whole can then respond by fleeing, hiding or adopting a defensive position.

     But this information is not always reliable. When predators are harder to identify, perhaps because they are well camouflaged, an animal may be more likely to mistake unrelated sounds or movements for a predator. Research found that bumblebees were more likely to produce false alarms having previously been exposed to highly camouflaged goldenrod crab spiders than bees that were unaccustomed to them.

     Some species are instead simply more vulnerable to predators than others. This can be because they are not fast enough to escape a close encounter or not equipped to fight a predator off. For these species, ignoring a true alarm is more likely to result in death, so it may be beneficial to follow a “better-safe-than-sorry” principle and pay the cost of being occasionally wrong. Willow tits produce alarm calls in response to most large aerial objects including planes and crows. This is because they are typically hunted in ambush attacks in which they are unlikely to escape. So the costs of alarm calling at a few planes becomes dwarfed by the threat of being killed in an attack.

(Adapted from https://www.thesouthafrican.com/animals/why-prey-animals-often-see-threats)

Câu 4: Cho biểu đồ:

SỐ LƯỢT KHÁCH VÀ DOANH THU TỪ CÁC CƠ SỞ LƯU TRÚ DU LỊCH

NƯỚC TA GIAI ĐOẠN 2017 - 2021

(Số liệu theo Niên giám thống kê Việt Nam 2022, https://www.gso.gov.vn)

Căn cứ vào biểu đồ, so với năm 2019 thì năm 2021, tổng lượt khách du lịch giảm bao nhiêu triệu lượt khách? (làm tròn kết quả đến hàng đơn vị của triệu lượt khách).

Một loài thực vật, cho cây thân cao, quả ngọt (P) tự thụ phấn, thu được F1 gồm 4 loại kiểu hình, trong đó số cây thân thấp, quả chua chiếm 4%. Biết rằng mỗi gene quy định một tính trạng, các allele trội là trội hoàn toàn; không xảy ra đột biến nhưng xảy ra hoán vị gene ở cả quá trình phát sinh giao tử đực và giao tử cái với tần số bằng nhau. Theo lí thuyết, các phát biểu sau đây đúng hay sai?