Question

The African savanna is a tropical grassland ecosystem mostly of grasses and few trees. One of the most recognizable trees in the African savanna is the acacia tree. It has many features that help it survive in this ecosystem.

The African acacia tree is tall with a domed top. The domed shape helps with photosynthesis and protects the leaves from drying winds. It has long tap roots, which allow it to reach water deep underground. Like the grasses in the ecosystem, the acacia uses energy from the Sun to turn matter from the environment into a usable form of food. Acacia trees reproduce through seed pods. The hard seeds within the pods have a nutritious coating that surrounds them. Seeds are disbursed by wind and animals. The seeds pass through the animals unharmed.

Acacia trees have long, extremely sharp thorns along their branches, protecting their delicate leaves from most hungry animals. Giraffes are able to eat the leaves of acacia trees due to their long, flexible tongues, which they use to move around the sharp spikes. In the process of being eaten, acacia leaves can produce a poisonous compound, making the leaves taste bitter. The trees also release a gas that warns other trees nearby to produce the compound as well. Giraffes have to eat quickly in order to avoid bitter leaves. Some acacias also have stinging ants that live inside of hollowed-out thorns. The ants receive shelter and food from the tree. They eat the nectar and seed coatings, dropping the seeds. If an animal tries to eat the leaves, the ants will sting the animal.



Some features of the acacia tree are shown.



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What happens to the atoms of the food molecules when the giraffe eats the acacia leaves?


The atoms are broken down and destroyed.


Different atoms form during chemical reactions.


New atoms are created and form new molecules.


The atoms are rearranged to form new molecules.

Answer 1

The atoms are rearranged to form new molecules.

Explanation: Digestion and metabolism break chemical bonds in the leaf molecules but do not destroy or create atoms. The atoms are conserved and are recombined into new molecules (nutrients, body tissues, CO2, H2O, wastes) during chemical reactions.