Life-or-death subject confronts the students of PBS’ ‘Degrassi High’

Summer vacation is over and school’s back in session--for the students at Degrassi High. PBS’ realistic program based in a fictional high school returns for its fourth and final season Monday, ushering in a new year of large and small dramas. Still not shying away from controversial issues, “Degrassi High” will tackle such subjects this season as teen suicide, parents’ extramarital affairs and sexual abuse.

This season’s first episode, a two-parter, brings up the issue of AIDS, during “Sexual Awareness Week” on campus. While the students marvel that condom machines have been installed in the boys’ and girls’ restrooms, one student is revealed to have been exposed to the AIDS virus. On a lighter note, another student takes on an unusual bet: vowing to walk naked through the lunchroom to earn money for his dream car.

“Degrassi High,” Monday 7:30-8 p.m. and Saturday 8-8:30 a.m. KCET. For 13- to 18-year-olds

MORE KIDS’ SHOWS:

The 1990 comedy Spaced Invaders (today 7 p.m.; Monday 2 p.m.; Saturday 7 p.m. Disney Channel) follows the adventures of some rather dimwitted Martians who happen to intercept the signal from a rebroadcast of Orson Welles’ “War of the Worlds” and think their leaders forgot to tell them about a planned attack on Earth. Ariana Richards, Douglas Barr and Royal Dano are among the human stars. For ages 8 and up.

The acclaimed series Avonlea (Monday 8 p.m.; Wednesday 1 p.m.; Saturday noon Disney Channel) returns for its second season. Based on the stories by Canadian author Lucy Maud Montgomery, “Avonlea” stars Sarah Polley as the precocious Sara Stanley, who has been sent to live with her deceased mother’s relatives on Prince Edward Island. This year, “Avonlea” will feature several guest stars, including Madeline Kahn, Peter Coyote and Michael York.

For ages 8 and up.

Disney’s animated “DuckTales” (Monday-Friday 4 p.m. KCAL) presents a special five-part segment, “Gizmoduck,” which chronicles the transformation of the wacky accountant Fenton Crackshell into the crime-fighting robot Gizmoduck. For ages 3 and up .

This week, Showtime unveils its new animated series We All Have Tales (Tuesday 7:30 p.m. Showtime), which features children’s stories from around the world, narrated by international stars. The series premiere “The Fool and the Flying Ship” is a Russian tale about a country fool who builds a flying ship and ends up winning the hand in marriage of the Tsar’s daughter. Oscar-winning William Hurt of “The Kiss of the Spider Woman” and “Broadcast News” narrates. For ages 6 and up.

Khrystyne Haje of ABC’s sitcom “Head of the Class” gets serious as the host of Spaceship Earth: Our Global Environment (Tuesday 8:30 p.m. Disney Channel). The half-hour special examines the Earth’s critical environmental problems and presents workable solutions. Also included is a visit with the British rock star Sting, who shares his experiences in Brazil’s rain forests. For ages 10 and up.

For the past 70 years the lovable Felix the Cat has been entertaining audiences with his hilarious exploits. Now he’s the star of his own animated film, Felix the Cat (Thursday 7 p.m. Disney Channel). When a princess from a legendary kingdom in another dimension is captured by an evil inventor, her teardrop, which contains her reflection, blasts through our dimension. Naturally, it ends up in the paws of Felix, who, with his best pal Poindexter, devises a plan to rescue her. For ages 6 and up.

Everyone’s favorite singing crab Sebastian from the 1989 animated feature “The Little Mermaid” hosts his own musical special, Sebastian’s Caribbean Jamboree (Friday 7:30 p.m. Disney Channel), which just also happens to be the title of his current hit sing-along album. The special, filmed at Walt Disney World, features a combination of stage performances and music video. Of course, Sebastian will sing the Oscar-winning tune “Under the Sea.” The very talented Broadway performer Samuel E. Wright supplies the voice for Sebastian. For ages 5 and up.

We’ve all gone through it. It’s near the end of the school year and your creativity has already gone on summer vacation. That’s exactly what happens to grade school student Katie in the new Special Delivery: Drawing a Blank (Saturday 3:30 p.m. Nickelodeon). It’s the last week of school and Katie’s favorite teacher gives her an assignment and Katie must struggle to muster up the creativity to do it. For ages 8 and up.