Final answer:
Plants in deserts and subtropical deserts need adaptations like deep root systems to access groundwater and mechanisms for minimizing water loss, such as a thick cuticle and reduced foliage (option b). They also benefit from having seeds capable of surviving long periods of dormancy and a rapid reproductive cycle following rain.
Step-by-step explanation:
Deserts and subtropical deserts are characterized by low precipitation and temperature extremes. For plants to survive in such environments, they need a range of adaptations. One key adaptation is having reduced leaf surface area to minimize water loss through transpiration - this would be more in line with having smaller leaves rather than broad ones. Furthermore, desert plants often have deep root systems to access groundwater and thick waxy cuticles to reduce transpiration.
Some desert plant adaptations include fleshy leaves with sunken stomata which help to reduce water loss. Many desert plants are also annuals that can grow and reproduce quickly following rainfall events. They're adapted to live with long periods of dormancy, surviving off the water they've stored during the infrequent rainy periods. These plants should also have seeds that can remain dormant during prolonged dry spells, ready to germinate when conditions are favorable.
Therefore, the most accurate answer to which adaptations plants in deserts and subtropical deserts should have to survive and reproduce would be options (b) deep root systems to reach groundwater and (d) a high reproductive rate to compensate for harsh conditions, with an emphasis on conserving water by having reduced foliage or water-storing features.
Hence, the answer is option b.