Hello. I've done well with everything else, but I'm stuck on the following:

1. Herring are salt-water fish. They

A - need to expel large amounts of water to offset osmosis
B - need to take in large amounts of water to offset osmosis
C - slowly dehydrate over the course of their lives
D - slowly swell up over the course of their lives

2. Some species of lungfish breathe only air; they have no gills, and will drown if forced underwater. Why might it be an advantage for lungfish to breathe air even though they live in water?

3. Bar-headed geese fly over the world's highest mountain range, the himalayas, at heights of 25,000 feet. What adaptations do you think they have which allow them to fly so high?

Muchos thanks in advance!

Hello! I'd be happy to help you with your questions. Let's break them down one by one:

1. To determine what herring need to do in terms of water balance, we need to understand osmosis. Osmosis is the movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. In this case, we're talking about the concentration of salt in the water.

Herring are saltwater fish, which means they live in an environment with higher salt concentration than their bodies. Therefore, they need to prevent excessive water loss due to osmosis.

Now let's analyze the options:

A - Need to expel large amounts of water to offset osmosis: This option is incorrect. Herring do not need to expel large amounts of water because they actually want to prevent excessive water loss.

B - Need to take in large amounts of water to offset osmosis: This option is correct. Herring need to take in large amounts of water to offset the loss of water through osmosis.

C - Slowly dehydrate over the course of their lives: This option is incorrect. Herring do not slowly dehydrate because they have mechanisms to prevent excessive water loss.

D - Slowly swell up over the course of their lives: This option is also incorrect. Herring do not slowly swell up because they actively regulate water balance.

Therefore, the correct answer is B - Herring need to take in large amounts of water to offset osmosis.

2. Lungfish are unique because they can breathe air despite living in water. To understand why this would be advantageous, we need to consider the oxygen availability in water compared to air.

Water contains significantly less oxygen than air, so for an aquatic animal to rely solely on gills to extract oxygen, it needs to be in an environment where oxygen is readily available. However, by being able to breathe air, lungfish can access a much higher concentration of oxygen compared to what is available in water. This allows them to supplement their oxygen needs, especially in environments where the water might be poorly oxygenated or stagnant.

So, the advantage of lungfish being able to breathe air even though they live in water is that it provides them with an additional source of oxygen, increasing their chances of survival in various aquatic habitats.

3. Bar-headed geese fly at extraordinary heights over the Himalayas, which are the world's highest mountain range. To understand their adaptations for flying at such high altitudes, we need to consider the challenges they face, primarily the reduced oxygen availability and the low air pressure at high altitudes.

Some possible adaptations that allow bar-headed geese to fly so high could include:

- Efficient respiratory system: They likely have highly efficient lungs to extract oxygen from the thin air at high altitudes.
- Adapted cardiovascular system: Their heart and circulatory system may be optimized to deliver oxygen efficiently to their muscles and tissues.
- Enhanced oxygen-carrying capacity: Bar-headed geese may have adaptations that increase their blood's oxygen-carrying capacity, such as higher hemoglobin levels.
- Strong wing muscles: Flying at high altitudes requires more effort due to the thinner air, so they may have well-developed wing muscles to provide the necessary power for sustained flight.
- Energy conservation techniques: To conserve energy during flight, they may utilize efficient wing flapping patterns or take advantage of updrafts and wind currents.

These are all potential adaptations that could help bar-headed geese fly at high altitudes. However, it's important to note that scientific research is ongoing, and there may be more specific mechanisms yet to be fully understood.

I hope this helps! Let me know if you have any further questions.