Read the text and choose the correct answer to fill in the numbered blanks.

A food web, a diagram (1) ______________ how plants and animals in an ecosystem rely on each other for food, is crucial to understanding nature's balance. At the top of the food web are animals, (2) ______________. These top animals are known as predators, and the ones they eat are their prey. Some animals can eat many different foods, while others eat only specific things.

When acid rain falls, it can increase the acidity of the water in lakes and rivers, (3) ______________ to the death of small water plants known as phytoplankton. Since insects eat phytoplankton, a decrease in food sources may result in a fall in insect (4) ______________. These insects are essential food for many other animals, such as fish, birds, frogs, and salamanders. The animals that eat these insects will have less food (5) ______________, and this shortage of food will move up the food chain.

Even if acid rain doesn't directly harm a specific plant or animal, its effects can still be significant for the entire food web. (6) ______________, if phytoplankton dies due to acidic water, and consequently, insects decrease in number, the animals that depend on these insects for food could (7) ______________. Thus, the overall food supply in the ecosystem can be reduced, impacting all the plants and animals within it.

Read the text and decide if each sentence is True, False or Not given.

Mammals are complex and often considered the smartest animals. They use advanced forms of communication, like humans using language and apes using sign language.

There are two other mammals that also seem to use an advanced form of communication. Dolphins and whales are unique mammals living in the ocean. Unlike fish, they don't have gills. Instead, they use blowholes on their heads to breathe. They come up to the water's surface regularly to get the air they need.

Dolphins and whales use a special kind of sound called sonar to navigate and communicate underwater. This sound bounces off objects and returns to them, helping them understand the size, shape, and distance of things around them. They also use these sounds to chat with each other! Unlike fish, they give birth to live babies and feed them milk. Even though they live in water, they have hair, which is quite surprising, and thick skin that protects them from the cold and from predators in the ocean.

You might also be surprised to learn that bats are also mammals. Bats fly like birds, but they do not have the other characteristics that birds have. Bats have fur, not feathers. Their arms have wing-like flaps of skin, but they are not like bird wings. Bats also give birth to live young and they produce milk. So, scientists classify bats as mammals.

Here's an interesting fact: not all mammals give birth to live young. The duck-billed platypus and spiny anteater both lay eggs like birds and some reptiles but have all the other characteristics of mammals. Good luck finding one. They are very rare! Mammals have their fair share of odd members, like the duck-billed platypus. But the basic characteristics—hair, backbone, milk, warmblooded— are always present in mammals no matter what.

Read the text and write NO MORE THAN TWO WORDS in each blank.

Pollinators, such as most bees and some birds, bats, and other insects, play a crucial role in flowering plant reproduction and producing most fruits and vegetables. Examples of crops that are pollinated include apples, squash, and almonds. Without the assistance of pollinators, most plants cannot produce fruits and seeds. The fruits and seeds of flowering plants are an essential food source for people and wildlife. Some of the seeds that are not eaten will eventually produce new plants, helping to maintain the plant population.

A recent study of the status of pollinators in North America by the National Academy of Sciences found that populations of honey bees (not native to North America) and some wild pollinators are declining. Declines in wild pollinators may result from habitat loss and degradation, while declines in managed bees are linked to disease (introduced parasites and pathogens).

Pollination results when the pollen from the male part of the flower (stamen) is moved to the stigma of the same or another flower and fertilizes it, producing fruits and seeds. Some flowers rely on the wind to move pollen, while other flowers rely on animals to move pollen.

Animals visit flowers in search of food and sometimes even mates, shelter, and nest-building materials. Some animals, such as many bees, intentionally collect pollen. In contrast, others, such as many butterflies and birds, move pollen incidentally because the pollen sticks to their body while collecting nectar from the flowers. All of these animals are considered pollinators.

Read the text and choose the correct answer.

1. Humans need access to fresh water to survive. However, they can harm this resource through pollution and land changes, like building on wetlands or blocking rivers. Wealthier countries can afford to build clean water systems, but poorer countries often lack the resources, making them more vulnerable to severe droughts.

2. Droughts can harm the biodiversity of a region. Worldwide, more than 125,000 animal species live in freshwater, like 15,000 types of fish, 4,300 amphibians, and 5,000 mollusks such as clams and oysters. Many species, including humans, depend on freshwater. Reduced freshwater availability can result in the death of many animals, and in extreme cases, entire species may become extinct, leading to a decline in regional biodiversity. In regions like Africa, it's getting longer because of climate change and more people needing water. For example, a drought in Kenya from 2007 to 2009 caused over 60 elephants to die from thirst, hunger, and sickness because of weak immune systems. Endangered animals like the white rhinoceros also got hurt, making them more at risk of disappearing.

3. Loss of biodiversity because of droughts affects people in many ways. In places relying on tourism, droughts can hurt the local economy. If fewer tourists come because of less wildlife, the locals may lose jobs and face poverty. They might start farming to earn money, using even more scarce water and worsening the drought. Also, when biodiversity drops, it can mess up the food chain, causing food shortages. For instance, if a kind of freshwater frog dies out because of a drought, the birds that eat these frogs may also decrease because of less food. Meanwhile, the insects the frogs used to eat could increase because there are fewer predators.