DOVER — In the busiest day of the legislative session thus far, lawmakers heard arguments on bills ranging from marijuana to standardized testing to taxation.

With the session ending for the year after June 30, legislators are seeking to pass proposals they see as critical, while many also float favored niche bills.

The Delaware Senate passed a bill allowing parents to opt their children out of the statewide Smarter Balanced assessment, although the legislation will head back to the House, which it had previously cleared, as a result of two new amendments.

House Bill 50, which backers say would codify the already existing right of parents to elect not to have their children take the state’s standardized test, also serves as a sharp critique of Gov. Jack Markell’s education policy.

The teacher’s union gave a vote of no confidence to Education Secretary Mark Murphy in March, and a growing number of lawmakers have taken steps to alter what they see as poor decision-making handed down from the executive branch.

Passage of the bill would be a rebuke of top education officials, and while the proposal did advance through the Senate by a 14-7 vote, it now must be passed again by the House.

One amendment expands opt-out rights from just the Smarter Balanced test, something clarified in a previous House amendment, to all state- or district-wide tests.

The second change would allow high school juniors to simply elect not to take the Smarter Balanced test.

The first amendment, from Sen. David Sokola, D-Newark, expands the scope of the proposal. While it passed the House easily in May, the changes could lead to more votes in opposition.

Gov. Markell has been publicly critical of the bill but has not said as to whether he will veto it. If he vetoes it after the session concludes on June 30, the Legislature would have three days once the session resumes in January to override the veto.

Should that effort fail, the process would start over again.

Another committee heard arguments in favor of and against decriminalizing marijuana.

House Bill 39, which passed the House earlier this month and now moves to the Senate chamber, would replace the criminal penalty for marijuana possession of one ounce or less with a civil punishment of a $100 fine.

Using marijuana or carrying more than an ounce of cannabis could still lead to jail time, as could possession by individuals less than 21 years old.

During the hearing in the Senate Judiciary Committee, a representative for the Police Chiefs’ Council said the organization believes one ounce is too much. While the council would not back the bill if the amount is changed, it would not oppose it either, Executive Director Martin Johnson said.

Several speakers testified they were marijuana users and felt the penalties are unnecessarily harsh. Someone caught carrying a few grams of marijuana can face criminal charges, something bill supporters want changed.

Sen. Greg Lavelle, R-Sharpley, acknowledged an arrest for possession can have a negative impact on a person’s job or college prospects, but said he was concerned that decriminalizing the drug would create a slippery slope that could lead to legalization.

The bill did not receive any support from Republicans in the House. While the vote results were not available as of Wednesday night, main sponsor Rep. Helene Keeley, D-Wilmington, said she believed it would get out of committee.

She’s hopeful the bill will pass before the session ends. It could be heard as soon as today.

Two bills that would raise taxes for wealthy Delawareans also were released from committee.

House Bill 181 would create new tax rates of 7.1 percent at $125,000 and 7.85 percent at $250,000. The current top bracket is $60,000, with a rate of 6.6 percent.

House Bill 196 would institute a 7.05 percent rate for adjusted gross income between $125,000 and $250,000 and 7.8 percent for income greater than $250,000. It also aims to reduce itemized deductions for citizens making at least $125,000.

House Bill 181 would generate another $21.6 million in the upcoming fiscal year, and House Bill 196 would bring in an additional $18.8 million, according to Department of Finance estimates.

The legislation, which was filed by Rep. John Kowalko, D-Newark, on Tuesday, was approved by the House Revenue and Finance Committee.

“It shows a striking acknowledgement of the crisis we are facing as far as having adequate revenue to continue providing the services that we are obligated to provide,” Rep. Kowalko said.

The state is facing a projected shortfall of about $171 million for the fiscal year starting July 1, 2016.

Rep. Kowalko said he intends to present House Bill 196 to the full House soon.