You use "hay" when talking about the existence of something or to indicate there is/there are. For example, "hay un perro en el parque" (there is a dog in the park). You use "estar" to express a temporary state or condition, such as emotions, locations, or physical states. For example, "estoy cansado" (I am tired) or "estamos en la playa" (we are at the beach). You use "tener" to indicate possession, age, or to express physical sensations. For example, "tengo un libro" (I have a book), "tengo veinte años" (I am twenty years old), or "tengo hambre" (I am hungry). **

In Spanish, "tener que" means "to have to" or "must." It is a common phrase used to express obligation or necessity. For example, "Tengo que estudiar" means "I have to study." **

"Hay que" and "tener que" both express the idea of necessity, but they are used in slightly different contexts. "Hay que" is used to express a general obligation or necessity, often referring to a rule, law, or social norm. For example, "Hay que estudiar para tener buenas notas" (One must study to get good grades). On the other hand, "tener que" is used to express a specific obligation or necessity that is related to a particular person or situation. For example, "Tengo que terminar este informe antes de la reunión" (I have to finish this report before the meeting). **

The verb "tener que" is conjugated in the preterite tense by using the preterite form of the verb "tener" followed by the infinitive form of "que." For example, "tuve que" (I had to), "tuviste que" (you had to), "tuvo que" (he/she/it had to), "tuvimos que" (we had to), "tuvieron que" (they had to). This construction is used to express that someone had an obligation or necessity to do something in the past. **

"Tener que" is used when referring to a specific person or group of people who have an obligation or necessity to do something. For example, "Tengo que estudiar" (I have to study). On the other hand, "Hay que" is used when talking about a general obligation or necessity that applies to everyone. For example, "Hay que respetar las reglas" (One must respect the rules). So, the choice between "tener que" and "hay que" depends on whether the obligation is specific to an individual or more general. **

Yes, there is a form of extreme hiking camping known as backpacking or wilderness camping. This type of camping involves carrying all necessary gear and supplies on your back and hiking long distances to remote and rugged locations. Backpacking often requires a higher level of physical fitness, outdoor skills, and self-sufficiency compared to traditional camping. It can be a challenging and rewarding way to experience the wilderness in a more immersive and adventurous way. **

While camping and hiking, you can enjoy various outdoor activities such as fishing, bird watching, stargazing, and wildlife spotting. You can also explore the natural surroundings by taking nature walks, swimming in nearby lakes or rivers, and even trying out some outdoor cooking. Additionally, you can challenge yourself with hiking to scenic viewpoints, setting up a campfire, and simply relaxing and enjoying the peacefulness of nature. **

These hiking pants, mountain pants, or outdoor pants are known by outdoor enthusiasts, hikers, mountaineers, and anyone who enjoys spending time in nature. They are designed to provide comfort, durability, and functionality for outdoor activities, making them popular among those who engage in hiking, trekking, camping, and other outdoor adventures. Additionally, outdoor retailers, gear shops, and online stores that specialize in outdoor equipment and apparel also carry these types of pants and are familiar with them. **