Final answer:
Venus's surface is composed of 75% lowland lava plains with volcanic features and coronae, shaped by subsurface volcanism and tectonics, and has a thick CO₂-rich atmosphere contributing to its extreme temperatures.
Step-by-step explanation:
The surface of Venus is dominated by about 75% lowland lava plains, and it is characterized by two distinct features: numerous volcanic features, and many large coronae. The coronae are indicative of subsurface volcanism, which, along with widespread tectonics driven by mantle convection, shapes the complex patterns of ridges and cracks on the planet's surface. The high continental region known as Ishtar Terra is one example of such tectonic activity. Although Venus's surface conditions are incredibly hostile, with a pressure of 90 bars and temperature of 730 K, it has been directly probed by several Russian Venera landers. Furthermore, Venus's thick atmosphere, composed primarily of carbon dioxide (96%) contributes to a severe greenhouse effect, maintaining the planet's extreme surface temperatures.