Trong chăn nuôi, người ta sử dụng tối đa bao nhiêu biện pháp dưới đây để tăng hiệu quả kinh tế?

I. Luôn đảm bảo tỉ lệ giữa số lượng con đực và số lượng con cái là 1/1.

II. Điều chỉnh mật độ đàn vật nuôi phù hợp.

III. Nuôi ghép các loài vật nuôi có ổ sinh thái khác nhau về thức ăn.

IV. Cung cấp đầy đủ lượng thức ăn cần thiết.

Cho hàm số \(f(x) = \cot x,x \ne k\pi ,\forall k \in \mathbb{Z}.\)

Healthy mind, healthy body

“A healthy mind lives in a healthy body” is a saying (1) ______ to have often been used by the ancient Greeks. Thousands of years later, the same idea still applies. According to health experts, it’s advisable (2) ______ eight to ten glasses of water every day. However, water itself is not enough; a balanced diet is essential, too. A healthy body naturally is the result of doing exercise. Many people, however, do not like gyms and object to going there for different reasons. Some, for instance, say that aerobic sessions are too difficult to follow while others say that gyms are just too expensive. Many people also say that they have (3) ______ in finding time to exercise due to their busy lifestyle, but the truth is that everyone can make a little time every now and then. Regardless of the way people choose to exercise, it is important to remember that there’s no point (4) ______ doing it only for a short period of time. Last but not least, (5) ______ a positive attitude and doing away with negative thoughts contribute to one’s good health. In short, following (6) ______ surely helps in having a healthy mind and body.