The clean air act of 1963 was an improvement over the air pollution control act of 1955 because it
provided twice as much money for the study of air pollution
set limits on emissions from factories
set limits on emissions from vehicles
prevented the deforestation of national parks

Correct

set limits on emissions from factories

The Air Pollution Control Act of 1955 was the first federal legislation related to air pollution.

The Clean Air Act of 1963 established a federal program within the US Public Health Service. and authorized the investigation of techniques to monitor and control air pollution in factories.

they are best described as reliable search engines.

b. major john c. frémont led a rebellion called the bear flag revolt.

explanation:

during the bear flag revolt, from june to july 1846, a small group of american settlers in california rebelled against the mexican government and proclaimed california an independent republic. the republic was short-lived because soon after the bear flag was raised, the u.s. military began occupying california, which went on to join the union in 1850. the bear flag became the official state flag in 1911.