Problem: Wood:

In diffuse-porous woods the pores are evenly sized so that the water conducting capability is scattered throughout the growth ring instead of being collected in a band or row. Examples of this kind of wood are alder, basswood,[citation needed] birch, buckeye, maple, willow,and the Populus species such as aspen, cottonwood and poplar. Some species, such as walnut and cherry, are on the border between the two classes, forming an intermediate group.[citation needed]

What species do aspen, cottonwood, and poplar trees belong to?
---
A: Populus

Problem: Botany:

The root system and the shoot system are interdependent the usually nonphotosynthetic root system depends on the shoot system for food, and the usually photosynthetic shoot system depends on water and minerals from the root system. Cells in each system are capable of creating cells of the other and producing adventitious shoots or roots. Stolons and tubers are examples of shoots that can grow roots. Roots that spread out close to the surface, such as those of willows, can produce shoots and ultimately new plants. In the event that one of the systems is lost, the other can often regrow it. In fact it is possible to grow an entire plant from a single leaf, as is the case with Saintpaulia, or even a single cell which can dedifferentiate into a callus (a mass of unspecialised cells) that can grow into a new plant. In vascular plants, the xylem and phloem are the conductive tissues that transport resources between shoots and roots. Roots are often adapted to store food such as sugars or starch, as in sugar beets and carrots.

What happens if a plant looses roots or its shoots?
---
A: can often regrow it

Problem: Economy of Greece:

Between 1949 and the 1980s, telephone communications in Greece were a state monopoly by the Hellenic Telecommunications Organization, better known by its acronym, OTE. Despite the liberalization of telephone communications in the country in the 1980s, OTE still dominates the Greek market in its field and has emerged as one of the largest telecommunications companies in Southeast Europe. Since 2011, the company's major shareholder is Deutsche Telekom with a 40% stake, while the Greek state continues to own 10% of the company's shares. OTE owns several subsidiaries across the Balkans, including Cosmote, Greece's top mobile telecommunications provider, Cosmote Romania and Albanian Mobile Communications.

How many shares of OTE does the Greek state sell?
---
A: unanswerable

Problem: Treaty:

In the United States, the term "treaty" has a different, more restricted legal sense than exists in international law. United States law distinguishes what it calls treaties from executive agreement, congressional-executive agreements, and sole executive agreements. All four classes are equally treaties under international law; they are distinct only from the perspective of internal American law. The distinctions are primarily concerning their method of approval. Whereas treaties require advice and consent by two-thirds of the Senators present, sole executive agreements may be executed by the President acting alone. Some treaties grant the President the authority to fill in the gaps with executive agreements, rather than additional treaties or protocols. And finally, congressional-executive agreements require majority approval by both the House and the Senate, either before or after the treaty is signed by the President.

What type of agreement requires majority approval by both the House and the Senate before or after a treaty is signed by the United States president?
---
A:
congressional-executive agreements